Keywords

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Trees, shrubs or herbs, some stoloniferous or with shoots arising from roots, all assumed or known to be semiparasitic; stems sometimes (Exocarpos) phyllocladic. Leaves alternate, rarely paired, expanded and petiolate or scale-like, or both, estipulate, mostly glabrous and with pinnate venation. Inflorescences various, or inflorescences lacking; in Phacellaria, many flowers emerging mostly from just above the internodes, apparently endogenously (Danser 1939) and flanked by minute bracteoles. Flowers actinomorphic, usually subtended by a primary bract and sometimes, as in some Thesium species and in Thesidium, also by two prophylls; bract and prophylls in Quinchamalium connate to envelop the entire ovary in a sclerenchymatous cover. Primary bract often connate with the floral pedicel, as in Thesium. Flowers mostly bisexual; calyculus absent, although a constricted rim may be present directly below the petals; petals (3) 4 or 5, valvate, distinct or basally coherent to connate; stamens as many as the petals and opposite them, epipetalous, placed at various heights on the petals, and usually with a characteristic tuft of hairs behind the anthers; filaments often short or lacking; a slight basal disk, lobed between petals, sometimes present; anthers short or long, 4-loculed, longitudinally dehiscing; in Choretrum anthers sessile, with 4 globular locules separately dehiscing. Pollen “nearly spherical to ellipsoid, smooth or finely reticulate”. Ovary inferior (more or less superior in Anthobolus and Exocarpos), short or elongate, with one locule, from the center of which arises a basal, frequently twisted funiculus suspending 3 pendent, ategmic ovules; Anthobolus and Exocarpos with a central, undifferentiated basal mamelon containing the embryo sacs. Fruit a drupe, usually with fleshy outer tissues and hard inner shell, containing a single seed embedded in copious, oily endosperm; germination mostly epigaeous, rarely (Comandra) hypogaeous and cryptocotylar (Kuijt 1978).

Thirty-six genera with several hundred spp., throughout the temperate and tropical regions of the World; the genus Thesium by far the largest with probably more than 300 spp., especially in arid regions of southern Africa; the family being absent, except for a single species of Acanthosyris in Costa Rica, from Mesoamerica and the Caribbean.

Vegetative Anatomy and Morphology. A curious structural feature in the stoloniferous genera Arjona and Comandra is the fact that roots developed from the rhizome always take their origin directly above axillary buds (Kuijt 1969). A further peculiarity is that the scale-bearing tips of the rhizomes are recurved, the apical meristems in effect facing backwards. Whether other stoloniferous genera like Geocaulon, Nanaodea, Nestronia, and Quinchamalium share such features is not known. Some species of Thesium are also rhizomatous.

Leaf and Wood Anatomy. The leaves of Santalaceae have a more or less collenchymatous subdermal layer. Usually, there is a standard division of the mesophyll into spongy and palisade parenchyma, but some species have anatomically isolateral leaves, like Arjona, Jodina, and Leptomeria. There are various forms of crystals and some sclereids. Vein endings are supplied with small clusters of storage tracheids.

The xylem consists mostly of numerous fiber tracheids with bordered pits, with a scattering of small vessel members characterized by simple perforation plates. The wood of Okoubaka is remarkable in having sparse, wide vessel elements with simple perforations and scattered, vertical, apotracheal wood parenchyma (Normand 1944).

Parasitism. Parasitism has been demonstrated in the great majority of Santalaceae (Kuijt 1969; Der and Nickrent 2008; Table 4), and is assumed to be a general feature. The plants may be parasitic on either roots or branches of the host, depending upon the taxon under discussion. Der and Nickrent (2008) have introduced the term amphiphagy for “species variably root and/or stem parasitic”, but they appear not to have realized the inherent problems with this concept. Parasitism on stems in Santalales requires the evolution of specialized adhesive tissues that allow seeds to remain attached to the host during germination, as in branch-parasitic mistletoes, including those here retained in Santalaceae (Kuijt 1990). The great majority (perhaps all) of these plants have also evolved primary haustoria that frequently have evolved further structural or physiological modifications of the cell layer that first establishes contact with the host. The extreme of such modifications are seen in Passovia (Loranthaceae; Dobbins and Kuijt 1974). However, such “adhesive” modifications are useless in terms of terrestrial or hypogeous germination. No known root-parasitic Santalales seem to have evolved primary haustoria; equally significantly, no root-parasitic members of the order (including the loranthaceous genera Atkinsonia, Gaiadendron, and Nuytsia) have viscin tissues surrounding their seeds. If the root parasitism in the relevant cases turns out to be attachments to exposed host roots, then the question becomes simpler. It is clear that such aspects are in great need of clarification in the Santalaceous genera involved.

The essential features of the initial phase of haustorial development in Santalaceae have been outlined in the introduction to Santalales. Since no studies exist of the endophyte per se except in Comandra (Toth and Kuijt 1977) and Exocarpos bidwillii (Fineran 1964), we may assume it to be, in most cases, a relatively simple wedge of tissue with minor vascular connections to the host xylem, most of the interface consisting of parenchyma. However, in Comandra it is known that endophytic filaments can actively invade the host xylem members. Its endophyte may undergo considerable fragmentation; entry of uniseriate filaments or single cells through the host’s bordered pits has been documented, as well as longitudinal growth of an initially uniseriate filament within a host tracheary element (Toth and Kuijt 1977). In Exocarpos bidwillii, long and slender, digitate processes form in the endophyte, growing parallel to the host organ, the innermost portion being a keel-like ridge that becomes embedded in host xylem. Individual files of vessel elements with simple perforations are present in older portions (Fineran 1963). In the hyperparasitic genus Phacellaria, no study of the endophyte exists, but the scattered distribution of shoots emerging from the endophyte (see Kuijt 1969, his Fig. 3-7a) surely indicates a very diffuse endophyte.

Inflorescence Structure. Inflorescences tend to be simple or sparsely branched as in Santalum and most herbaceous taxa; in form they may be spicate, racemose, or corymb-like. In Phacellaria, we cannot speak of inflorescences unless the entire shoot is meant.

FloralStructure andEmbryology. Santalaceous flowers lack a calyx, although a slight constriction below the petals may occur that may be even slightly lobed where the 3–5 petals meet. The petals are mostly distinct but sometimes partly connate below. The ovary is inferior except for the semi-inferior to nearly superior condition in Anthobolus and Exocarpos. Nearly all Santalaceae have bisexual flowers, Geocaulon having 3-flowered inflorescences where the middle one is bisexual and lateral ones functionally male only. Stamens are epipetalous and occur in the same number as the petals, usually with short, distinct filaments, but in other cases anthers are sessile or nearly so. Both uni- and bisexual flowers occur, especially in Anthobolus and Exocarpos, the latter also showing intermediate conditions (Stauffer 1959). It is common, but not universal, to find a distinctive tuft of hairs on the petal directly behind the stamen (Quinchamalium lacks such hairs). The style in the family is simple, topped by a nearly undifferentiated stigma. A basal glandular disk may be present adaxially to the petals, in a few cases being lobed between them, as especially in Acanthosyris.

As in most members of Santalales, the ovary of Santalaceae contains a single chamber in the center of which stands a structure that represents the evolutionary fusion of a number of ovules, mostly on a contorted stalk or funiculus. In some genera, like Phacellaria and Quinchamalium, the funiculus is absent, and we find a structure not unlike the ovarian papilla of most mistletoes. The ovules are greatly reduced; in some genera (Comandra, Thesium), an integument may still be recognized, but in others (Santalum, Mida) the distinction between integument and nucellus is lost, and in several advanced genera even the ovule is scarcely definable.

Much has been made in the past of the taxonomic significance of major types of embryo sac development such as the prevalence of the Polygonum type in all Santalales except Viscaceae and a few others. Zaki and Kuijt (1994, 1995), studying Viscum minimum, however, have shown that different patterns may exist in a single species, rendering the taxonomic status of this feature debatable. The same is indicated by the fact that both of the above types of development occur in different species of Olax (Olacaceae; Agarwal 1963).

In a number of genera studied, the embryo sac, like that of Loranthaceae, invades adjacent gynoecial tissues. The case of Quinchamalium is perhaps an extreme one, in which the antipodal end of the embryo sac, sealed off by a cross wall, forms a branched haustorial organ reaching into the apex of the ovarian papilla while the pole containing the egg apparatus swells up in clavate fashion. The egg apparatus remains in the papilla but, remarkably, the two synergids each produce a slender tube that grows into the style for about 1/3 of its length (Agarwal 1962). As in some other genera (and in at least some Olacaceae), even the endosperm produces some haustorial structures.

Perhaps more representative of the family is the embryo sac of Comandra, where a lateral caecum forms just below the egg apparatus and grows into the convoluted funiculus for some distance. Eventually, the endosperm consumes other papillar tissues and even some of the ovary wall (Ram 1957). Coalescent, multiple endosperm as in Loranthaceae has been reported in Santalum (Paliwal 1956). In Exocarpos, an octopus-like embryo sac, with upward extensions, eventually fills the entire ovarian cavity (Ram 1959). Since most genera of the family have not been accounted for in this regard, more unusual situations may well await us.

Pollen andPollination. Pollen in Santalaceae is mostly isopolar, but is distinctly heteropolar in Anthobolus, Arjona, Comandra, Myoschilos, Mida, Osyridicarpus, Quinchamalium and many, but not all, species of Thesium. The amb is commonly triangular or nearly so, but tetrahedral in Myoschilos. Arjona is unusual in having a sharply triangular amb, one face being separated into three separate portions (Feuer 1977). Sculpting in the family is highly variable, ranging from psilate through tuberculate and areolate to spinulate. Anthobolus and Exocarpos, while in other respects very similar, have a very distinct morphology in that the former is echinate-perforate and the latter muricate-striate (Lobreau-Callen 1982).

Pollination in Santalaceae has not received much attention, but is apparently effected by small bees, flies, and beetles. In some Thesium species, the flower is known to close during adverse weather or at night.

Karyology. Known chromosome numbers in the family include 13, 14, and 26, the latter apparently representing tetraploidy.

Fruit,Seed, andDispersal. The fruit of Santalaceae is either a nutlet or a drupe, the latter with a fleshy, sometimes brightly colored surface tissue as in Geocaulon, Nanodia, and Thesidium. In Jodina, the fleshy exocarp splits into five easily detached segments, and similar developments occur in Cervantesia and Staufferia. In Exocarpos, and to a lesser extent in Anthobolus, the adjacent pedicel swells up and becomes brightly colored, giving rise to the local name “cherry with the stone outside”, and clearly represents an adaptation to animal dispersal, perhaps the Casuaris. Thesium alpinum is said to be myrmechocorous, a small, yellow elaiosome being developed from the nearby floral pedicel (Ulbrich 1907). In the several genera of the family that are arboreal parasites, fiber-like processes emerge from the fruit wall upon digestion in the animal gut that function as attachment structures to potential host branches when voided (Danser 1940, 1955).

Germination and Parasitism. In terrestrial Santalaceae, germination mostly appears to be epigeous, that of Comandra, Santalum, and Thesium being hypogeous; however, seedlings of the great majority of the genera involved have not been described. In Comandra (Kuijt 1978) and Santalum, we find instances of cryptocotylar germination.

The most intriguing members of the family undoubtedly are the branch-parasitic mistletoes of tropical Asia and northern Australia, especially the unique, squamate genus Phacellaria that very much resembles Arceuthobium in Viscaceae. Unfortunately, there are some important gaps in our knowledge about some of these genera, and their taxonomic status is by no means clear. Phacellaria, however, is a very distinctive taxon, sharply delimited from the others, and probably representing a quite separate line of evolution. From herbarium material—and by extrapolation from Arceuthobium—we may make certain deductions. Specimens often produce a swelling on the primary host, always another mistletoe (Loranthaceae or another santalaceous mistletoe). Shoots are generated from the endophyte, often over a length of 10 cm (see illustrations in Danser 1939, who writes that stems emerge from host lenticels). These two facts signify that the endophyte is a greatly fragmented system, penetrating the host branch in both directions, in all likelihood through the cortex and phloem, as in Arceuthobium. It may also be suggested that early penetration probably proceeds from a primary haustorium representing the tip of the radicle, as in other advanced parasitic angiosperms. It would be interesting to find that, again as in other highly advanced mistletoes (Arceuthobium, Kuijt 1960; Viscum minimum, Kuijt 1986; Tristerix aphyllus, Kuijt 1988), all shoots are generated from the endophyte, the epicotylar portion of the seedling withering away following host entry. Careful field observations are needed, but their obvious difficulty lies in the host inaccessibility in the canopy of trees.

The other Asiatic ramal parasites have a very different habit from Phacellaria. They tend to form an irregular mass of partly creeping and intertwining growth on host stems. The primary locus of infection in such a plant is difficult to determine. Since no significant swellings seem to be present, and since there is no evidence of shoot generation from within host tissues, the structure of the haustorium almost certainly is a simple, limited one similar to that elsewhere in the family.

The haustoria of Buckleya are reported to remain alive (and presumably functional) for at least 15 years (Kusano 1902).

As far as known (with the above reservation on Phacellaria), the endophyte of Santalceae is a fairly simple wedge of tissue, with connections to host xylem and especially parenchyma. It is only in Comadra (Toth and Kuijt 1977) that a degree of endophytic fragmentation has been documented; from marginal areas, individual filaments of the endophyte may even grow into the length of a host xylary member, terminating in a single apical cell.

Hosts. As in most root parasites, little is known about the host ranges in Santalaceae. The exception, understandably, is in the genus Phacellaria, which is limited to other mistletoes, mainly Loranthaceae and Viscaceae (Danser 1939). The indications that elsewhere are available point to a lack of specificity in host choice, as in Anthobolus and Exocarpos (Stauffer 1959). Barber (1906) mentions more than a hundred hosts species for Santalum album, and Pizzoni (1906) gives a similar report for Osyris alba. Buckleya distichophylla seemed to prefer the roots of Tsuga canadensis until this was shown to be only a matter of co-occurrence (Piehl 1965). The same was true for Pyrularia until at least 63 host species of numerous genera and families were documented by Leopold and Muller (1983). Nestronia also scarcely appears to be host specific. As mentioned elsewhere, however, the identification of hosts in root parasites is usually a very cumbersome and labor-intensive enterprise, and generalizations may be premature.

Distribution. Santalaceae are found throughout the temperate and tropical world, the genus Thesium with perhaps more than 300 species being especially common in arid southern Africa. There is an unexplained large gap in family distribution in the Caribbean area, where no species are known, and in northern South America and Mesoamerica where, in the latter area, only Acanthosyris is known, and that only very rarely.

Even though molecular considerations have prompted Der and Nickrent (2008) and Nickrent et al. (2010) to move Anthobolus to Opiliaceae, I have been unable to devise a family description for that family that would include the genus. Anthobolus flowers have essentially sessile anthers, while those of Opiliaceae have distinct, often long, filaments. More important is the fact that no prominent disk or disk lobes exist in Anthobolus, while this is a defining feature in Opiliaceae. Nickrent et al. (2010) write of a calyculus in Anthobolus, but that is an error. Cystoliths are present in the leaves of Opiliaceae, but not in Anthobolus, an essentially leafless shrub. Finally, Anthobolus lacks differentiated ovules, instead forming a mamelon-like structure like that of mistletoes and Exocarpos, while Opiliaceae are characterized by a single, well-differentiated, pendent ovule (Stauffer 1959). Anthobolus is thus again included in Santalaceae in the present treatment where nearly all modern students, especially the monographer Stauffer, have located it near Exocarpos.

Fossils. The only more or less reliable Santalaceous fossils are a Thesium-like flower and two staminate flowers of Osyris from amber deposits in the Baltic Sea area (Pilger 1935).

Human Uses. Sandalwood trade. Santalum album and several related Santalum species continue to have significant commercial value because of the dense heartwood and the famous, fragrant essential oils; more details are provided in the introduction to Santalales. On the Juan Fernández Islands, this has led to the extermination of the native species S. fernandezianum (Mida salicifolia), one of two parasitic plants that have become extinct in recent history (the New Zealand mistletoe Trilepidia adamsii being the other extinct species).

Other uses. Tubers of some Arjona species are eaten by aboriginal peoples in southern Chile (Skottsberg 1916).

Systematics. Since my treatment of Santalaceae differs in significant respects from that of Nickrent et al. (2010), it is necessary to provide a justification of my views. In that study, an extreme position was taken in recognizing six families in what traditionally has been a single one, Santalaceae, s.l. It is apparent from the consensus phylogeny produced that those six families, plus Viscaceae, represent a monophyletic assemblage. The latter family was nevertheless retained “as this option results in less disruption of the existing system where it [Viscaceae] is well established and frequently used.” The recognition of the other six families was considered a cladistic consequence of or rather a sacrifice for maintaining Viscaceae as a family.

It has, however, proven exceedingly difficult to establish meaningful taxonomic distinctions between several of the resultant families, and the internal integrity of some of them seems dubious. In Nanodeaceae, for example, the claimed calyculus in Nanodea and Mida does not exist, and the “tetramerous” flower of the latter, in reality, is pentamerous (Cheeseman 1914). Nothing is known about the embryology of Nanodea, and this minute plant is scarcely a subshrub, contrary to what the authors imply (see Fig. 56 below). All this renders the combination of these two genera in one family very questionable. Another problem is seen in the fact that the genus Anthobolus is removed from Santalaceae and placed in Opiliaceae. Contrary to the authors’ statement, that genus is not at all morphologically compatible with Opiliacae, and in the present treatment is restored to Santalaceae where both Stauffer’s monograph (1959) and P. Hiepko’s personal judgment placed it. A third example of conflict is present in the authors’ inclusion of both Arjona and Quichamalium in Schoepfiaceae. Schoepfia is a pantropical shrub to 10 m high, differing in the inflorescence and other details; especially Arjona shows overwhelming correspondences with the Northern Hemisphere genus Comandra. The latter genus, placed with Geocaulon in a separate family, Comandraceae, is virtually impossible to separate from other Santalaceae at a family level. An admittedly difficult decision has here been to retain Eremolepidaceae as a family, as its derivation from Santalaceae seems well established, but I see it as a uniquely American evolutionary experiment involving, in at least one case, the independent origin of epicortical roots and, in all three genera, the independent origin of the primary haustorium and arboreal parasitism. In summary, I see no alternative but to return to the traditional view of Santalaceae.

Since various novel family placements for erstwhile Santalalean genera have been suggested mostly by Nickrent et al. (2010), it may be useful to summarize the different classifications in the following table.

Table 6 Family disposition of genera related to Santalaceae, s.l
Full size table

Key to theGenera of Santalaceae

  1. 1.

    Asiatic or Australian plants parasitic on branches, hyperparasitic on other mistletoes, or scandent on tree branches 2

  • Terrestrial plants (rarely attached to, or emerging from host stems: Daenikera); Old or New World; not hyperparasitic or scandent 4

  1. 2.

    Plants squamate, hyperparasitic, emerging from the host in clustered fashion; India and Malaysia to S China 26. Phacellaria

  • - Plants at least partly foliaceous, not hyperparasitic; Himalayas to New Guinea, New Caledonia, or N Australia 3

  1. 3.

    Plants with non-twining, foliaceous stems, lacking epicortical roots or secondary haustoria 12. Dufrenoya

  • Plants with twining, squamate stems producing secondary haustoria as well as straight, foliaceous, non-haustorial stem 11a & 11b. Dendrotrophe & Dendromyza

  1. 4.

    Phyllotaxy mostly paired or whorled 5

  • Phyllotaxy consistently alternate 11

  1. 5.

    Phyllotaxy whorled; New Caledonia 2. Amphorogyne

  • Phyllotaxy mostly paired; leaves lanceolate, apex acute; not on New Caledonia (except one species of Santalum with acute leaves) 7

  1. 7.

    Each pistillate flower solitary at the tip of a leafy shoot, with 4 long foliar bracts alternating with petals; staminate flowers lacking post-staminal hairs 5. Buckleya

  • Flowers mostly bisexual, or pistillate flowers either in axillary umbels or in panicles; post-staminal hairs present; flowers lacking foliaceous bracts 8

  1. 8.

    Rhizomatous shrub, dioecious or flowers bisexual; flowers in axillary umbels 21. Nestronia

  • Non-rhizomatous shrubs or trees; flowers mostly or always bisexual, inflorescence an axillary or terminal cyme or panicle 9

  1. 9.

    Branches complanate; petals 4; fruit a drupe 8. Colpoon

  • Branches terete or quadrangular when young; petals 4 or 5; fruit a nut 10

  1. 10.

    Stems quadrangular when young; inflorescence a small axillary, 1–5-flowered cyme; E South Africa 30. Rhoiacarpos

  • Stems terete when young; inflorescence an axillary or terminal panicle, often many-flowered; not known from South Africa 31. Santalum

  1. 11.

    Stiffly erect, dark purple, essentially leafless shrublet; New Caledonia 10. Daenikera

  • Erect or not, but not dark purple; leaves or leaf scales numerous, evident, rarely caducous; New Caledonia or elsewhere 12

  1. 12.

    Herbaceous plants, excluding those with a woody base and Daenikera 13

  • Woody plants, including those with a woody base and Daenikera 19

  1. 13.

    South America 16

  • Native to North America (Thesium introduced locally in Montana), Eurasia, or Africa (including Madagascar; one species of Thesium in SE Australia/Tasmania) 14

  1. 14.

    Plants glabrous or hairy, including floral parts; fruit a nutlet with distinctive surface veins; mostly Africa, Europe, Madagascar, SE Australia, Tasmania 36. Thesium

  • Plants and floral parts glabrous; fruit a drupe or nutlet, its surface smooth; North America (Comandra also in the Balkan area) 15

  1. 15.

    Inflorescences terminal, with numerous bisexual flowers; fruit greenish 9. Comandra

  • nflorescences 3-flowered, axillary; lateral flowers functionally male, central flower bisexual or pistillate; fruit orange 14. Geocaulon

  1. 16.

    Small, creeping herb; flowers in axillary groups of 3; petals 4, not formed into tube; the 4 more or less distinct stamens inserted on base of petals; fruit a red drupe, exocarp fleshy. Extreme southern South America and Falklands Islands 20. Nanodea

  • Erect plants; petals connate into a short or long floral tube, the stamens attached near its mouth; fruit a nutlet 17

  1. 17.

    Nutlet surface veined; S Brazil 35. Thesium brasiliensis & T. aphyllum

  • Nutlet surface not veined 18

  1. 18.

    Ovary and dry fruit ensheathed by a 3-toothed sclerenchyma envelope; subterranean tubers lacking 29. Quinchamalium

  • Ovary and fruit distinct; rhizome tips swelling tuber-like 4. Arjona

  1. 19.

    New World 20

  • Old World 25

  1. 20.

    Plants with short shoots, often in axils of spines; glandular disk with conspicuous, lateral, petal-like lobes 1. Acanthosyris

  • Short shoots absent; glandular disk without petal-like lobes 21

  1. 21.

    Leaves rhombic in shape, each side and the apex with a prominent spine 14. Jodina

  • Leaves otherwise, lacking lateral or terminal spines 22

  1. 22.

    Inflorescence a raceme but not catkin-like; E and SE United States 28. Pyrularia

  • Inflorescence catkin-like or a short cluster or cyme; South America 23

  1. 23.

    Young growth usually densely pilose, sometimes glabrescent; exocarp fleshy, splitting into 5 long segments reaching to the base 6. Cervantesia

  • Plants glabrous, fruit a drupe or nutlet but exocarp not splitting at maturity 24

  1. 24.

    Inflorescence catkin-like; flowers sessile; petals distinct; fruit a drupe. Argentina and adjacent Chile 19. Myoschilos

  • Inflorescence not catkin-like; flowers pedicellate; petals basally connate; fruit a nutlet; southern Brazil 36. Thesium brasiliensis & T. aphyllum

  1. 25.

    Australia, New Zealand, or SW Pacific Islands 26

  • Eurasia-Africa, including Madagascar and New Guinea 32

  1. 26.

    Petals conspicuously constricted basally; fruit truncate apically; New Zealand (North Island); extinct on Juan Fernández Islands 18. Mida

  • Petals without basal constriction; fruit not apically truncate; Australia (Exocarpos bidwillii in New Zealand) 27

  1. 27.

    Ovary superior; receptacle often enlarged and fleshy below drupe 28

  • Ovary (semi-) inferior; receptacle not enlarged or fleshy below drupe 30

  1. 28.

    Flowers prominently stalked 3. Anthobolus

  • Flowers sessile or nearly so 29

  1. 29.

    Plants dioecious; drupe more or less sessile, 6–7 mm long; receptacle not enlarged below drupe 23. Omphacomeria

  • Flowers bisexual; receptacle enlarged and fleshy below drupe; drupe up to 5 mm long 13. Exocarpos

  1. 30.

    Flowers in terminal, spiral spikes, without bracts 33. Spirogardnera

  • Flowers in axillary or lateral racemes or clusters, subtended by a bract or bracteoles 31

  1. 31.

    Each flower subtended by 2 or more bracts 7. Choretrum

  • Each flower subtended by a single bract 17. Leptomeria

  1. 32.

    Shrubs; petals basally connate; fruit a small nutlet with conspicuous surface venation 36. Thesium

  • Trees or shrubs; petals not basally connate; fruit often a drupe, its surface smooth 33

  1. 33.

    Mediterranean to China, or Africa, including Madagascar 34

  • Neither Mediterranean nor African-Madagascan (but Canary Islands included) 40

  1. 34.

    Madagascar 39

  • Mainland Africa and tropical Asia 35

  1. 35.

    Each flower with 2 prophylls 35. Thesidium

  • Flowers lacking prophylls 36

  1. 36.

    Flowers sessile; inflorescence with stellate pubescence 22. Okoubaka

  • Flowers pedicellate or, if sessile, inflorescence without stellate pubescence 37

  1. 37.

    Twigs angular when young; petals 3 or 4; Mediterranean and Africa to China 25. Osyris

  • Twigs not angular when young; petals 4 or 5; Africa, Ceylon, India to New Guinea 38

  1. 38.

    Inflorescence mostly a 3-flowered cyme; Africa 24. Osyridicarpos

  • Inflorescence spike-like, racemic, or catkin-like; Ceylon and India to New Guinea 32. Scleropyrum

  1. 39.

    Drupe strongly 5-grooved 34. Staufferia

  • Drupe not 5-grooved 27. Pilgerina

  1. 40.

    Flower with 1 bract and 2 bracteoles; drupe grooved; Canary Islands 16. Kunkeliella

  • Flower lacking bracteoles; fruit smooth; not on Canary Islands 41

  1. 41.

    Base of fruit surrounded or clasped by swollen, bright-colored pedicel 13. Exocarpos

  • Base of fruit lacking expanded pedicel 42

  1. 42.

    Leaves leathery, linear to broadly elliptical, to 5 cm long; fruit mostly spherical; Mediterranean and montane paleotropics 25. Osyris

  • Leaves leathery or thin, not linear, to 15(20) cm long; fruit mostly pyriform; E USA and parts of SE Asia 43

  1. 43.

    Leaves leathery; Sri Lanka, India, Malacca, Laos, New Guinea 32. Scleropyrum

  • Leaves thin; E and SE USA, and Central to E Himalayas 28. Pyrularia

Genera of Santalaceae

  1. 1.

    Acanthosyris (Eichler) Griseb.

    Acanthosyris (Eichler) Griseb., Goetting. Abhandl. 24: 151 (1871).

    Osyris sect. Acanthosyris Eichler (1868).

Trees or shrubs, often with thorns and/or short shoots subtended by the ovate-elliptical or falcate, alternate leaves; spines subtending short or long shoots, or spines absent, young organs in part pubescent (incl. the abaxial surface of petals) or glabrescent. Inflorescence a short-pedunculate cyme of 3–5 flowers, axillary to the scale leaves at the base of short shoots or spines. Flowers bisexual, fragrant, mostly 5-merous; post-staminal hairs present; stamens as many as petals; stamen filaments short, thick, distinct, perhaps adhering to the adjacent petals by its sticky hairs, basally attached to and opposite the petals; glandular disk extending into prominent, somewhat fleshy lobes between the petals; ovary semi-inferior; ovules 3, pendent from the top of a convoluted funiculus but facing upwards. Fruit globular, nut-like, petals persistent, but exocarp fleshy, greenish to yellowish-orange, edible; endosperm solid, embryo extremely small.

Five spp., South America, from S Brazil, SE Bolivia and Uruguay to the Río Paraguay estuary. A new species, A. annonagustata, has been described from E Ecuador (Ulloa and Jorgensen 1998) and has recently been collected in Costa Rica, suggesting that it may be present in Panama as well.

  1. 2.

    Amphorogyne Stauffer & Hürlim.

    Amphorogyne Stauffer & Hürlim., Vierteljahrsschr. Naturforsch. Gesellsch. Zürich 102: 337–349 (1957).

Shrubs or small trees, glabrous, with forked branching; innovations of a single internode terminated by a whorl of (usually) 4 leaves. Leaves leathery, oblanceolate to spatulate, apex rounded, often with small mucro, base tapering to very short petiole, venation pinnate, the midvein raised abaxially. Inflorescences racemose, axillary (or terminal?), lateral units single, pedicellate flowers or few-flowered, pedunculate groups. Flowers pedicellate; petals 5(6), deltoid; stamens as many as the petals and basally united with them, with post-staminal hair tufts; filaments short; anthers bilocular, dorsifixed; ovary inferior, indistinguishable from the tapered pedicel; style short and stout, stigma truncate, somewhat 3- or 4-lobed. Fruit a one-seeded, ellipsoid drupe; exocarp membranaceous, mesocarp fleshy, endocarp hard, embryo dicotylous.

Two spp., endemic to New Caledonia.

  1. 3.

    Anthobolus R. Br.

    Anthobolus R. Br., Prodr. Fl. Nov. Holl. (1810); Stauffer, Mitteil. Bot. Mus. Univ. Zürich 213: 1–260, tab. 1–3 (1959), rev.

Xerophytic, glabrous, much branched shrubs, sometimes ± leafless, semiparasitic; internodes terete to angular. Leaves alternate, linear to lanceolate, apetiolate or nearly so, often caducous. Inflorescences axillary, few-flowered racemes, the staminate 3–8-flowered, pistillate mostly 1-flowered. Dioecious. Flowers pedicellate, with 3–5 petals. Staminate flowers: petals oval to deltoid, lacking calyculus or articulation below the petals; stamens as many as the petals, opposite and united basally with the petals; anthers 2-loculed, dorsi- or basifixed, dehiscing with a longitudinal slit; post-staminal hairs absent; filaments very short, disk small, vestigial style lacking; pollen tricolporate. Pistillate flower: petals tongue-shaped, articulate at their base, this resembling a very small calyculus; sterile stamens and disk lacking; ovary superior, conical-ovoid, stigma sessile, 3–5-lobed; ovarian cavity simple, placenta conical, ovules not differentiated. Fruit ca. ellipsoid, the pedicel swollen and elongated; exocarp red to orange, mesocarp fleshy and sticky, endocarp bony, finely grooved. Seed solitary, embryo dicotylous.

Three spp., northern half of Australia.

Molecular data have led Nickrent et al. (2010) to place Anthobolus in Opiliaceae, but there are several strong arguments against that view, as described above under the family discussion.

  1. 4.

    Arjona Cav.

    Arjona Cav., Icon. 4: 57, t. 383 (1797).

Rhizomatous, herbaceous plants or (more rarely) subshrubs, some rhizomes swelling into small fusiform (edible) tubers that regenerate the plant in the following growing season, the rhizome tip recurved. Shoots dimorphic, some unbranched and sterile, others terminating in an inflorescence. Leaves alternate, linear to lanceolate, stiff, acute. Inflorescence a terminal spike of crowded, white to purplish red flowers. Flowers bisexual, distylous, the 4 or 5 petals basally united into a tube that is often hairy outside; stamens with short filaments attached to mouth of tube; post-staminal hairs present; glandular disk cushion- or ring-shaped, persistent on the fruit; ovary inferior; calyculus not recognizable; style filamentous, exceeding the floral tube; stigma 3-lobed; ovules 3, pendent from a central, stout, straight funiculus. Fruit a small nutlet. n = 14.

About a dozen spp., N from Tierra del Fuego at least as far as Peru, Argentina, and southern Brazil.

Molecular evidence has led Nickrent et al. (2010) to place Arjona (with Quinchamalium) in their Schoepfiaceae (Olacaceae), a suggestion that is here rejected.

  1. 5.

    Buckleya Torrey

    Buckleya Torrey, Amer. J. Sc. 45: 170 (1843), nom. cons. # 2109; Carvell & Eshbaugh, Castanea 47: 17–37 (1982), rev.

Shrubs; leaves narrowly ovate leaves with short petioles and acute apex, phyllotaxy decussate. Dioecious, sterile organs of the opposite sex lacking. Male inflorescence a small umbel, staminate flowers small, without calyculus; petals 4, each basally with an epipetalous stamen; post-staminal hairs absent; glandular disk prominent, square. Pistillate flowers solitary at the end of leafy shoots, subtended by pairs of scale leaves; the 4 deltoid petals alternating with 4 elongated green bract-like organs; glandular disk square; style straight, stigma 4-lobed; ovary inferior, much elongated; ovules 3 or 4, very small, pendent from the tip of a central funiculus. Fruit a dry nut, exocarp thin, endocarp stony, embryo dicotylous.

Five spp., one in E North America, 4 in E Asia.

  1. 6.

    Cervantesia Ruíz & Pavón

    Cervantesia Ruíz & Pavón, Fl. Peruv. Chil. Prodr.: 39, t. 7 (1794).

Small trees with ovate to elliptical, alternate leaves, young growth and abaxial leaves densely pilose, less so adaxially, or glabrescent. Inflorescences small clusters of flowers, axillary or in terminal arrangement. Leaves alternate, the blades ovate to elliptical, sometimes coriaceous. Flowers bisexual; petals 5, with associated post-staminal hairs; stamens with short filaments, epipetalous; anthers with 4 elongated locules dehiscing with a combined longitudinal slit; receptacle somewhat cupular around the ovary, which is initially distinct but gradually becomes nearly inferior; style short, stout, stigma indistinctly 2- or 3-lobed; ovarian cavity simple, with contorted funiculus and 2 or 3 apically pendent ovules. Fruit drupe-like, red or blue, 1-seeded, exocarp fleshy, divided into 5 long segments reaching to the base, endocarp stony, usually with 2 or 3 long slits. Seed spherical, embryo dicotylous.

Three or four spp., Peru and Ecuador.

  1. 7.

    Choretrum R. Br.

    Choretrum R. Br., Prodr. Fl. Nov. Holl. 1: 354 (1810).

Small shrub often with rod-like branches, much branched, with small, usually long-persistent, alternate scale-leaves. Flowers small, solitary or clustered, axillary, each with 2 or more small bracteoles, bisexual, often with small teeth between the petals; petals 5, thick, erect, the acute tip bent inwards, covering the 5 epipetalous stamens; glandular disk weakly 5-lobed; filaments very short, anthers dorsifixed, with 4 inward-facing locules dehiscencing introrsely and separately; style very short, stigma 5-lobed; ovary broadly top-shaped, semi-inferior, united with the obconical pedicel. Fruit globular to ellipsoid, bearing the persistent petals; exocarp thin, coriaceous-fleshy, endocarp stony, thick.

Six spp., Australia.

  1. 8.

    Colpoon P. J. Bergius

    Colpoon P.J. Bergius, Descr. Pl. Cap. Bon. Spei 38, t. 1, fig. 1 (1767).

Small trees or shrubs with complanate branches. Leaves paired (more or less alternate on very vigorous shoots), coriaceous, elliptical to obovate. Inflorescences small, terminal racemes, naked below and distally with small, nearly capitate clusters of to 10 flowers, with caducous, narrow bracts. Flowers bisexual or pistillate with aborted stamens; petals 4, blunt; stamens 4, opposite, short, with sparse post-staminal hairs; anthers with 4 locules, longitudinally dehiscent; glandular disk weakly 4-lobed; ovary inferior; style short, stigma with 4 short lobes; ovarian cavity simple; ovules 4 or 5, pendent from a stout, central funiculus, facing upwards. Fruit a drupe with enlarged pedicel, reddish to brown, obovoid or ellipsoid, bearing the persistent petals; exocarp fleshy, endocarp stony; embryo dicotylous, cotyledons very short.

One sp., Colpoon compressum P.J. Bergius, South Africa.

  1. 9.

    Comandra Nuttall

    Comandra Nuttall, Gen. N. Amer. Pl. 1: 157 (1818); Piehl, Mem. Torrey Bot. Club 22: 1–97 (1965), rev.

Perennial, glabrous, rhizomatous plants to 30 cm high; rhizomes stout, their roots with numerous haustoria, the subterminal portions swollen into slender tubers, the rhizome tips curved backwards; shoots dimorphic, some vegetative, unbranched, others with a terminal inflorescence. Leaves lanceolate, often glaucous when exposed. Inflorescence branched, with numerous, bisexual, whitish to pinkish flowers subtended by small, linear bracts. Flowers bisexual; petals (4) 5, stamens as many, united basally with the petals and backed by a tuft of hairs; glandular lobes alternating with the petals; ovary inferior, obconical; style conical at the base, filamentous above; ovarian cavity simple, with 2 or 3 ovules pendent from contorted central funiculus. Fruit a dry, greenish-grey drupe, the petals persistent. n=13, 26, the latter for C. umbellata subsp. pallida.

One sp., C. umbellata Nuttall, N North America, the Balkans Peninsula and Romania.

  1. 10.

    Daenikera Hürlim. & Stauffer

    Daenikera Hürlim. & Stauffer, Vierteljahrsschrift Naturforsch. Gesellsch. Zürich 102: 332 (1957).

Small, erect, nearly leafless root parasite, purplish when fresh, glabrous, the lowest internodes much elongated. Inflorescence a small panicle with terminal flower below which are single flowers and triads in the axils of alternate bracts. Flowers minute, short-pedicellate, unisexual? Petals 4, ovate, erect, purplish; stamens (staminodia?) with one or two locules, anther ± dorsifixed on short filament, this united with the base of the petals; post-staminal hairs sparse; ovary more or less inferior, the (glandular?) part above the petals depressed-conical, grading into a very short style; stigma 2(3)-lobed; ovarian cavity simple, with 2 ovules attached to a short funiculus. Fruit a globular, small drupe or nut bearing the persistent petals, single-seeded.

One sp., Daenikera corallina Hürlim. & Stauffer; New Caledonia.

This curious species has been said to be amhiphagous (Hürlimann and Stauffer 1957; Nickrent et al. 2010). It is puzzling to find it attached to both host roots and host stems because each location requires a very different germination and establishment regime. It is conceivable that entrance took place subterraneously, structures like cortical stand traversing tissues into the stem and emerging there as shoots. For a discussion of the amphiphagy concept, see the introductory portions of the order.

  1. 11a.

    Dendrotrophe Miquel

    Dendrotrophe Miquel, Fl. Ind. Bat. 1: 779 (1856).

  1. 11b.

    Dendromyza Danser

    Dendromyza Danser, Nova Guinea, N.S., 4: 133 (1940); Danser, Nova Guinea, N.S., 6: 261–277, tab. 9–24 (1955), rev.

    Henslowia Blume (1850), p.p.

    Cladomyza Danser (1940).

Small bushes, some at least partly scandent, parasitic on tree branches; leaves alternate. Flowers very small, in small, axillary clusters or solitary, rarely bisexual, more commonly plants dioecious or monoecious; petals 5 or 6. Staminate flowers with flat receptacle; stamens with very short filament, epipetalous on petal base, post-staminal hairs present; anthers small, at the tip of the filament, dehiscing transversely. Pistillate flower with or without small sterile stamens; ovary inferior; glandular disk concave or convex; stigma essentially sessile, with 2–5 lobes; ovarian cavity simple; ovules 2 or 3, pendent from the tip of a short, thick placental column. Fruit a small drupe, spherical to ovoid; exocarp fleshy, endocarp hard. Seed solitary, with prominent longitudinal furrows; embryo with 2 cotyledons, these often connate.

At least 21, poorly known spp., India to S China, the Philippines, Melanesia and N Australia.

The genera Dendromyza and Dendrotrophe at present seem inadequately separated and are provisionally placed together in the present treatment. The only generic contrasts in Danser’s writing seem to lie in the nature of the mesocarp fibers and the surface features of the endocarp (smooth in Dendromyza, more or less tuberculate in Dendrotrophe). It is unfortunate that Danser was never able to revise Dendrotrophe, his 1940 listing of 10 species being but a preliminary effort; his 1955 paper was published posthumously. The extensive use he made of fruit characteristics requires confirmation with modern anatomical methods, using a greater selection of species. Perhaps more importantly, there is a need for detailed field observations on the events leading to germination and initial establishment on the host (as there is for Dufrenoya), as well as the mature mode of parasitism (twining vs. non-twining, epicortical roots, secondary haustoria). The above description is an amalgam of information from the two genera.

At least some species show dimorphism in branches, a twining type of branches being squamate and bearing haustoria, and a second type being non-twining and leafy, mostly without haustoria; this is a remarkable parallel to Cuscuta (Convolvulaceae; see Kuijt 1969).

There are some isolated items of information that merit inclusion. van Steenis (1933) claimed that Dendrotrophe umbellata is non-parasitic, a view doubted by Danser (1940). Hambali (1977) later stated that the species is parasitic on nearby epiphytes, and that at maturity it produces thick branches that may also parasitize the branches of the supporting tree.

The seedlings of Cladomyza dendromyzoides Stauffer become attached to the host branch, where it produces a sinuous radicle that follows host contours (Kuijt 1990). In C. cuneata, the endosperm is deeply lobed and contains a minute embryo of a broadly fusiform shape, extending into two distinct, narrow cotyledons. Dendromyza reinwardtiana seeds have elongated, acicular, fibrous vascular bundles from the ovary wall that appear to provide an attachment mechanism to the host, comparable to viscin. Its two cotyledons, still recognizable by the shallow grooves delimiting them, are completely connate. The conclusion must be that Cladomyza and Dendromyza are cryptocotylar in germination. The great reduction of the radicular pole, in turn, suggests (but does not prove) the formation of a primary haustorium as well as subsequent shoot production from the endophyte. Dendrotrophe stems generate many epicortical roots bearing secondary haustoria.

  1. 12.

    Dufrenoya Chatin

    Dufrenoya Chatin, Compt. Rend. Acad. Paris 51: 657 (1860).

    Henslowia Bl. (1850), p.p.

    Hylomyza Danser (1940).

Glabrous parasitic plants on tree branches, stems neither twining nor bearing epicortical roots or secondary haustoria. Leaves expanded, alternate, base acute, apex rounded. Dioecious, the flowers small. Male inflorescence a (sometimes compound) umbel with one terminal and several lateral flowers, the peduncle with scale leaves, those of the upper and lower part forming an involucre. Staminate flower with 5 deltoid petals and 5 stamens inserted below them; disk 5-lobed, flat. Pistillate flowers solitary, sessile, the peduncle similar to the staminate one; ovary inferior; petals 5, deltoid, with 5 sterile stamens inserted below them; disk 5-lobed, flat; style short; stigma with 5 slender, spreading lobes. Fruit a drupe, petals persistent; mesocarp with radially aligned, membranous fibers. Seed sometimes furrowed longitudinally; embryo with 5 parallel ridges that extend both upwards and downwards.

Perhaps 11 spp., Thailand, Malaysia, and Indonesia.

  1. 13.

    Exocarpos Labill. Figs. 52–54

    Fig. 52.
    figure 1

    Santalaceae. Exocarpos menziesii. A Flowering shoot. B Leaves. C Inflorescence. D Flower, seen from above. E Branchlet with mature fruit. F Endocarp. G Seed, longitudinally sectioned. (Stauffer 1959, drawn by L.-M. Stauffer-Imhoof)

    Full size image
    Fig. 53.
    figure 2

    Santalaceae. Exocarpos neo-caledonica. A Young axis. B Flowering phylloclade. C Inflorescence. D Fertilized flower, longitudinal section. E Stamen. F Very young fruit. G Mature fruit with pedicellar cupule. H Endocarp. (Stauffer 1959, drawn by L.-M. Stauffer-Imhoof)

    Full size image
    Fig. 54.
    figure 3

    Santalaceae. Exocarpos latifolia. A Flowering branch. B Leaf base. C Two spikes. D Pistillate flower with lobed disk. E Petal with stamen. F Median section of staminate flower showing pistillodium. G Bisexual flower. H Fruit attached to swollen pedicel. (Koorders and Valeton 1914, drawn by M. Mangoendimedjo)

    Full size image

    Exocarpos Labill., Rel. Voy. Rech. Pérouse 1: 155. 1798, nom. cons. # 2097; Stauffer, Mitteil. Bot. Mus. Univers. Zürich 213: 1–260, tab. 4–20 (1959), rev.

    Sarcopus Gagnepain (1946).

    Sarcopodaceae Gagnepain (1947).

    Sarcopodales Lam (1948).

Woody plants variable in stature, mostly glabrous, ranging from dwarf shrubs to trees 20 m high, semiparasitic; lateral roots with numerous haustoria, at times generating shoots; internodes variable in shape, terete, angular, or flattened into phylloclades. Leaves alternate, distichous when with phylloclades, rarely paired, at times reduced to scales in flowering areas, often heterophyllous. Flowers bisexual or unisexual when sterile organs of the opposite sex present; sex distribution often not clear. Inflorescences diverse, essentially spike-like, sometimes compound, when small often condensed in leaf axils, when terminal with basal bracts, or axillary, rarely reduced to a single flower. Flowers small to minute, often in depressions on the axis, sessile or rarely short-pedicellate; petals 3–8, mostly glabrous on both sides but sometimes pilose, deltoid to oval; stamens isomerous, opposite and basally attached to the petals, filaments very short, dorsi-basifixed, the 4 locules dehiscing longitudinally; post-staminal hairs lacking; pollen tricolporate, barrel-shaped; glandular disk with short lobes alternating with the petals, united with the ovary; ovary mostly semi-inferior, the distinct part conical, stigmatic lobes usually alternating with petals; ovary 1-chambered, placenta a central cone lacking differentiated ovules, embryo sacs developing in the apex of the placental cone. Fruit superior to semi-inferior; base of fruit encased by the greatly expanded, red pedicel. Embryo dicotylous. n=10.

Twenty-six spp., many variable, Annam and E Java through Indonesia to New Caledonia, Australia, Tasmania, New Zealand, and many South Pacific Islands, including Hawai’i.

It has been reported (Lam 1945) that E. pullei is both a stem and a root parasite, but this needs confirmation (see the introduction to Santalales). As mentioned previously, the genus Exocarpos was at the center of a curious error of interpretation that had unusual nomenclatural consequences. Impressed by what they thought was a basically gymnospermous position of the ovules, Gagnepain and Boureau (1947) described Sarcocarpus aberrans Gagn., and even the Sarcopodaceae Gagn. One year later, Lam (1948) erected the Sarcopodales on that foundation, even though he had come to realize that the subject was a known species of Exocarpos, E. pullei Pilger.

  1. 14.

    Geocaulon Fernald

    Geocaulon Fernald, Rhodora 30: 23 (1928).

Slender, unbranched, rhizomatous perennials to 30 cm tall. Leaves alternate, ovate, thin, apex rounded, petiole short, venation evident. Flowers in axillary clusters of 3, the central one bisexual or pistillate, the two lateral ones functionally male; petals 5, reddish, spreading; anthers as many as the petals and opposite them; basal disk somewhat lobed; filaments broad, scarcely exceeding the lobes of the disk; anthers distinct from the sepals; post-staminal hairs present; ovarian cavity simple. Fruit a one-seeded drupe, orange-red, the exocarp juicy. n=13.

One sp., Geocaulon lividum Fernald, boreal forest from the Atlantic to Alaska, Canada’s Northwest Territories, and the B.C. coast, where rare.

Sex distribution in Geocaulon remains uncertain. The protologue (Fernald 1928) states the central one (rarely two) flowers to be bisexual, “the lateral mostly staminate and promptly dropping after anthesis, or sometimes all the flowers staminate”. Smith and Smith (1943) write that the central flowers are pistillate and the lateral ones staminate, representing monoecy.

  1. 15.

    Jodina Hook. & Arnott Fig. 55

    Fig. 55.
    figure 4

    Santalaceae. Jodina rhombifolia. A Flowering branch. B Flower, longitudinal section. C Mature fruit. D Same, longitudinally sectioned. E Embryo. (Pilger 1935)

    Full size image

    Jodina Hook. & Arnott, Hook. Bot. Miscell. 3: 172 (1833).

Much-branched shrubs or small trees to 4 m high, with alternate, rhombic, glabrous, stiff leaves, with one spine on each side and one at the apex; base of leaf cuneate, petiole essentially lacking. Inflorescence one or several small, pedunculate, axillary clusters of 7 or 8 flowers, with pubescent bracts. Flowers bisexual, lacking a calyculus; petals 4 or 5, abaxially densely pubescent, adaxially glabrous except for a large post-staminal tuft of hairs; stamens as many as the petals, united with them at their very base; anthers dorsifixed, with 2 elongated locules dehiscing with a common longitudinal slit, filament short and stout; ovary eventually inferior, with stout style, stigma blunt, weakly 3-lobed; ovarian cavity simple, with greatly contorted funiculus apically bearing 3 pendent ovules; glandular disk with large, dark green colored, erect lobes alternating with the petals; receptacle broad. Fruit globular, drupe-like, exocarp fleshy, rugose, pilose, divided into 5 longitudinal parts easily separating at maturity; endocarp stony, sometimes splitting into 2 or 3 parts. Seed solitary, globular, embryo ellipsoid, with two strap-shaped cotyledons.

One sp., Jodina rhombifolia Hook. & Arnott, S Brazil, S Bolivia, C Chile, Argentina S to Río Negro, Paraguay, and Uruguay.

  1. 16.

    Kunkeliella Stearn

    Kunkeliella Stearn, Cuad. Bot. Canar. 16: 11–26 (1972).

Virgate, squamate, erect, shrubby root parasites, branching sympodial. Leaf scales triangular, alternate. Inflorescence spike-like, with sterile bracts below, few-flowered. Flowers bisexual, small to minute, each subtended by a bract and two large, acute prophyllar bracteoles; petals 5, spreading, not articulate from the receptacle, post-staminal hairs present; stamens as many as the petals, attached to the glandular disk where continuous with the petal bases; anthers biloculate, dehiscing with longitudinal slits, filaments short, basifixed; pollen prolate, 3-colporate, smooth, with alveolate faces; ovary inferior, unilocular; ovules 3, pendent from the twisted central funiculus; style short, stigma truncate, entire, capitate. Fruit a small, globular, grooved, 1-seeded drupe, bearing the persistent petals; exocarp fleshy, endocarp stony; embryo dicotylous.

Four spp., Canary Islands.

  1. 17.

    Leptomeria R. Br.

    Leptomeria R. Br., Prodr. Fl. Nov. Holl. 1: 353 (1810).

Small shrubs, often much branched at the base, or shoots terminating in thorns, internodes strongly striate. Leaves squamate, alternate, usually dropping soon, if persistent acicular to obovate. Flowers either solitary in axillary positions or, more commonly, in numerous, short, axillary spikes; floral bracts persistent or caducous. Flowers very small, apparently always bisexual, sessile or short-pedicellate; petals 5, spreading, thick, somewhat thickened and incurved apically; glandular disk incised to lobed; stamens as many as the petals, opposite and basally united with them, minute; filaments nearly lacking; anthers with 4 locules facing inwardly and forming a circle; style and stigma minute, the latter weakly lobed; ovary inferior, top-shaped; ovarian cavity simple, ovules not clearly distinct from the central placenta. Fruit ellipsoid-globular, with persistent petals; exocarp thin, coriaceous, or juicy, endocarp thin, fragile; embryo very small.

Seventeen spp., Australia and Tasmania.

  1. 18.

    Mida A. Cunn. ex Endl.

    Mida A. Cunn. ex Endl., Gen. Pl. 5: 327 (1837).

    Santalum sect. Mida A. DC. in DC., Prodr. 14: 686 (1857).

Small tree to 8 m high or shrub with mostly alternate, shiny, lanceolate to obovate leaves. Inflorescence a small terminal or axillary, few-flowered panicle or raceme with up to 6 flowers. Flowers bisexual, mostly 5-merous (Cheeseman 1914); receptacle lacking a calyculus; petals ovate, constricted at the base; glandular disk with short, broad lobes between the petals; ovary semi-inferior; ovules 2 or 3. Fruit top-shaped, bright red, apex nearly truncate.

One sp., Mida salicifolia A. Cunn., New Zealand (North Island); extinct on Juan Fernández Islands, as Santalum fernandezianum Phil. or Mida fernandeziana (Phil.) Sprague & Summerh.

  1. 19.

    Myoschilos Ruiz & Pav.

    Myoschilos Ruiz & Pav., Fl. Peruv. Chil. Prodr.: 41, t. 34 (1794).

Small, glabrous shrubs; leaves alternate, ovate to oblong. Inflorescence catkin-like, with 1–2 catkins per leaf axil. Flowers sessile, bisexual, subtended by bracts; petals 5; anthers 5, epipetalous, filaments thread-like; anthers essentially basifixed, locules 4, ovoid, dehiscing introrsely with a common slit; glandular disk prominent, flat; ovary inferior, top-shaped; style short, slender, stigma with 2–5 perpendicular lobes; ovarian cavity simple, ovules 3–5, pendent from a central, stout funiculus, facing upwards. Fruit a drupe with persistent petals, and partly enveloped by bracts. Seed globular, embryo cylindrical, dicotylous.

One sp., Myoschilos oblongus Ruíz & Pavón, S Argentina and adjacent Chile.

  1. 20.

    Nanodea Banks ex C.F. Gaertner Fig. 56

    Fig. 56.
    figure 5

    Santalaceae. Nanodea muscosa. Fruiting plant from Sphagnum bog in Tierra de Fuego. (x 1.5, from Kuijt 1969, drawn by author)

    Full size image

    Nanodea Banks ex C.F. Gaertner, Fruct. 3: 251, t. 225 (1805).

Small, creeping, branched herbs, spreading by means of slender stolons, with narrowly linear or acicular, alternate leaves. Flowers small, in groups of three in axils of upper leaves, bisexual; calyculus absent (Dawson 1944); petals 4, stamens 4, opposite petals, filaments very short, locules 4, ovoid, dehiscing with a common slit; post-staminal hairs present; glandular disk concave, with short lobes between the petals; ovary inferior, top-shaped; style short, stout, stigma nearly spherical, weakly 2-lobed; ovarian cavity simple, with 2 ovules pendent from the central, short funiculus. Fruit a drupe, globular, red, exocarp fleshy, endocarp stony; embryo with 2 very small cotyledons.

One sp., Nanodea muscosa Gaertn. f., extreme South America, Staten and Falkland Islands. Pollination is by small flies (Skottsberg 1901–1903, p. 51).

  1. 21.

    Nestronia Raf.

    Nestronia Raf., New Fl. Amer. 3: 12 (1836).

Small, branching, glabrous, rhizomatous shrub to a meter high, hemiparasitic; leaves paired, lanceolate. Dioecious, or flowers bisexual. Male inflorescence an axillary, pedunculate umbel with 3–10 flowers lacking aborted style; pistillate flowers solitary, axillary; all flowers with obconical, inferior ovary; calyculus absent; petals 4(5), spreading, acute, puberulent along the margins; stamens 4(5), opposite, accompanied by post-staminal tuft of hairs; filament very short, attached to base of petals; style conical at base, stigma with 4 short lobes. Fruit an ellipsoid, small drupe.

One sp., Nestronia umbellula Raf., E United States.

  1. 22.

    Okoubaka Pellegr. & Norm. Fig. 57

    Fig. 57.
    figure 6

    Santalaceae. Okoubaka aubrevillei var. glabrescentifolia. A Tip of branch. B Inflorescence. C Flower bud. D Anthetic flower. E Flower, longitudinally sectioned. F Petal with stamen. G Young endocarp. (Louis and Léonard 1948, drawn by J.M. Lerinckx)

    Full size image

    Okoubaka Pellegr. & Norm., Bull. Soc. Bot. France 93: 139 (1946).

Tree to 40 m in height, its wood with sparse, wide vessel elements with simple perforations; new branches pubescent. Leaves alternate, short-petiolate, covered with simple hairs below, becoming glabrous. Panicles many-flowered, with stellate hairs. Flowers sessile, small, stellate-pubescent, by abortion more or less unisexual; petals 5, valvate; stamens 5, opposite petals; disk massive; ovary inferior, unilocular, with 3 ovules; style short; stigma lobed. Fruit a drupe. Seed one, ovoid; endosperm copious; embryo small.

One (2?) sp., Okoubaka aubrevillei Pellegr. & Norm., Ivory Coast and Gold Coast. Okoubaka, perhaps the largest tree of Santalales (if not of parasitic angiosperms generally), reputedly is an allelopathic tree, causing the death of surrounding vegetation; however, this effect may be the result of extensive root parasitism. The tree has a long history of medicinal and symbolic use by native people in West and parts of Central Africa, and ground bark products are still sold commercially for such purposes. Parasitism in Okoubaka has been documented by Swaine and Hall (1986), and by Veenendaal et al. (1996). The seed is the largest of any parasitic angiosperm (dry mass of 43 g).

  1. 23.

    Omphacomeria (Endl.) A. DC.

    Omphacomeria (Endl.) A. DC. in DC., Prodr. 14: 680 (1857).

Broom-like shrubs with scale-like, alternate, caducous leaves. Monoecious, flowers very small. Staminate flowers sessile, crowded in short axillary spikes, 4–6 at the tip of a thick peduncle, the mostly 4 petals ovate, spreading; glandular disk flat, scarcely lobed; stamens very small, filaments short, thick; anthers with 4 longitudinally dehiscing locules; aborted style very small or scarcely developed. Pistillate flowers solitary or in pairs, sessile, 5-merous, at the tip of a short, thick peduncle, sterile stamens poorly developed; style short, straight, stigma 2-lobed, sessile. Fruit an ovoid drupe, exocarp fleshy, endocarp stony.

One sp., Omphacomeria acerba (R. Br.) DC., SE Australia.

  1. 24.

    Osyridicarpos A. DC.

    Osyridicarpos A. DC. in DC., Prodr. 14: 635 (1857).

Shrubby plants, some scandent, twigs thin, not angular. Leaves alternate, lanceolate to ovate. Inflorescence a small, axillary, 3–7-flowered cyme, or flowers solitary, axillary. Flowers bisexual, 5-merous, without prophylls; petals with hair cluster behind the stamens; stamens connate with the base of petals; filament thin, short; glandular disk not clearly delimited; ovary inferior; ovules 2 or 3, pendent from the apex of a convoluted funiculus. Fruit nut-like, bearing the lower portion of the receptacle.

Six spp., South Africa and East Africa to Eritrea.

  1. 25.

    Osyris L.

    Osyris L., Sp. Pl.: 1022 (1753).

Dioecious shrubs or small trees, much branched; twigs angular. Leaves alternate, lanceolate to linear-lanceolate, evergreen, usually glabrous and coriaceous. Dioecious or polygamous. Petals 3 or 4, deltoid, calyculus absent. Staminate flowers in axillary, few-flowered cymes or racemes; style lacking; glandular disk prominent, flat; stamens as many as petals, distinct or nearly so, with small tufts of post-staminal hairs; anthers dorsifixed, 4-loculate, dehiscing with longitudinal slits.

Bisexual or pistillate flowers essentially sessile, solitary or in threes, mostly at the tip of small shoots; petals 3 or 4; glandular disk with short marginal tips alternating with petals; style stout, stigma with 3 or 4 lobes; ovary inferior, narrowly obconical, with a simple ovarian cavity; ovules 2–4, attached to the tip of a stout central funiculus, erect. Fruit drupe-like, spherical or ovoid, 1-seeded; petals persistent; exocarp somewhat fleshy, endocarp thin, stony; embryo dicotylous. n=15, 20.

Two spp., Mediterranean and tropical Africa to S China.

  1. 26.

    Phacellaria Benth. Fig. 58

    Fig. 58.
    figure 7

    Santalaceae. Phacellaria fargesii, parasitic on Taxillus sutchuensis. (From Kuijt 1969, drawn by author)

    Full size image

    Phacellaria Benth. in Benth. & Hook., Gen. Plant. 3: 229 (1880); Danser, Blumea 3: 212–235 (1939), rev.

Small, glabrous or short-tomentose, squamate, simple or sparsely branched plants of Arceuthobium-like aspect, sprouting diffusely from the stems of various genera of Loranthaceae (rarely from Dendrotrophe) or Viscaceae; scale leaves alternate. Flowers sessile in axils of scale leaves, singly or in small clusters, often in irregular longitudinal groups above the axils and with minute bracteoles, or sometimes terminal. Flowers unisexual, plants monoecious (rarely dioecious?), flowers sometimes bisexual. Petals mostly 4–8. Staminate flowers with short, epipetalous stamens, filaments very short and flat; anthers with 4 locules facing inwards, dehiscing with longitudinal slits; post-staminal hairs lacking; glandular disk flat; aborted style very small. Pistillate flowers lacking sterile stamens; ovary inferior; ovarian cavity simple, often 4–6-lobed, funiculus central, columnar, with 3(4 or 5?) pendent, ategmic ovules at the tip. Fruit an oblong drupe, bearing the persistent petals, exocarp fleshy; endocarp bony. Seed ellipsoid, apically 5-lobed; endosperm strongly lobed, embryo minute, completely undifferentiated, implying cryptocotyly.

Six or seven spp., India and Malaysia to S China.

Although no study of the endophyte is extant, it is clear that the latter must be greatly fragmented, as in Arceuthobium; it is also probable, again as in Arceuthobium, that the seedling’s epicotyl aborts and that, consequently, all shoots are produced from the endophyte. This, in turn, may imply the formation of a primary haustorium, probably the only one in Santalaceae.

  1. 27.

    Pilgerina Z.S. Rogers, Nickrent & Malécot

    Pilgerina Z.S. Rogers, Nickrent & Malécot, Ann. Missouri Bot. Gard. 95: 398–400 (2008).

Shrubs or trees to 12 m high. Leaves alternate, glabrous, elliptic to lanceolate, petiolate, venation pinnate. Inflorescence a (sub)terminal bracteate raceme with 8–23 flowers, slightly puberulent to nearly glabrous. Flowers bisexual, pedicellate, each subtended by a minute, often caducous bract; calyx absent; petals (4)5(6), distinct; stamens one opposite each petal and basally adnate with it, post-staminal hairs present; anthers dorsi-basifixed, locules 4, dehiscing introrsely by longitudinal slits; glandular disk fleshy, nearly circular, with slightly upturned rim where alternating with petals; ovary semi-inferior, the receptacle broad; ovarian cavity simple; ovules 1–3, pendent from a straight, central funiculus; style very short to absent, stigma essentially sessile, with 3–5 short lobes. Fruit a 1-seeded, broadly globular, glabrous drupe, petals persistent; exocarp fleshy, thin; mesocarp thin, stony, smooth or finely grooved; endocarp papery.

One sp., P. madagascariensis Z. S. Rogers, Nickr. & Malécot; endemic to Madagascar. Perhaps congeneric with Staufferia.

  1. 28.

    Pyrularia Michx.

    Pyrularia Mich., Fl. Bor. Amer. 2: 231 (1803).

Shrubs to 5 m high, root parasites. Leaves thin, linear, lanceolate, to broadly elliptical, puberulent when young, glabrescent in age, alternate. Dioecious or polygamous. Male inflorescence a raceme, many-flowered; fertile racemes shorter and with fewer flowers. Petals 5, ovate, tip acute, with post-staminal hairs. Staminate flowers in terminal, small, panicle-like groups, with short, obconical hypanthium; disk with 5 short, glandular lobes alternating with short stamens; anther locules elongate, dehiscing with a longitudinal slit; sterile pistil present; glandular disk with evident lobes alternating with petals. Pistillate flower with small, aborted stamens and short filaments; style short, stout; ovary top-shaped; stigma depressed-capitate; ovarian cavity simple, with few, erect ovules on twisted funiculus. Fruit pyriform to nearly spherical, a drupe with thin exocarp, petals persistent, mesocarp stony; embryo globular, dicotylous.

Two spp., one in the eastern United States S to Georgia, the other one in tropical parts of the Central and E Himalayas.

  1. 29.

    Quinchamalium Molina

    Quinchamalium Molina, Saggio Stor. Nat. Chile 151 (1782), nom. gen. cons. #2120.

Herbaceous plants, some with woody base, some rhizomatous, with distinct flowering and sterile shoots from the base, both unbranched. Leaves acicular to linear, acute, alternate. Inflorescence a terminal, often crowded spike or capitulum. Flowers bisexual, at least one species distylous, 5-merous, basally invested by an envelope consisting of the fusion between the bract and two prophyllar bracteoles, their tips distinct; floral tube elongated, flowers yellowish, often becoming reddish in age. Stamens bilocular, with short filaments attached to the mouth of the floral tube, without stamen hairs; anthers basifixed; style exceeding the floral tube; stigma capitate, with three short lobes; glandular disk fleshy, elevated, ring-shaped to nearly cupulate; ovules 3, pendent from a short, straight funiculus. Fruit a nutlet, enclosed by a sclerified envelope representing the bract and prophyllar bracteoles.

A taxonomically complex genus of perhaps 20 spp., S Chile and Argentina into Peru. Quinchamalium continues to be utilized as a folk medicine in southern Chile; I have seen it being gathered in large clumps, and have observed it for sale at a local market.

Molecular data led Nickrent et al. (2010) to place Quinchamalium (and Arjona) in their Schoepfiaceae, a suggestion that is here not followed, as explained further above.

  1. 30.

    Rhoiacarpos A. DC.

    Rhoiacarpos A. DC. in DC., Prodr. 14: 634 (1857).

Shrub with quadrangular internodes when young; leaves paired, ovate. Inflorescence a small axillary or terminal cyme, 1–5-flowered. Flowers bisexual, 5-merous; hair clusters behind the stamens; glandular disk with short, rounded lobes between the petals; ovary inferior; ovules 5, pendent from the central funiculus. Fruit an ovoid to gobular, edible nut; petals persistent.

One sp., Rhoiacarpos capensis (Harv.) A. DC., eastern South Africa.

  1. 31.

    Santalum L. Fig. 59

    Fig. 59.
    figure 8

    Santalaceae. Santalum album. A Flowering branch. B Flower. C Gynoecium. D Stamen, ventral view. E Same, dorsal view. F Fruit. G Same, longitudinal section. (Koorders and Valeton 1914, drawn by M. Mangoendimedjo)

    Full size image

    Santalum L., Gen. Pl., ed. 2: 165 (1742).

    Santalum sect. (Eu)Santalum L.

    Santalum sect. Hawaiiensia Skottsb., Proc. 4th Pac. Sci. Congress, Java 436 (1919).

    Santalum sect. Polynesica Skottsb., Proc. 4th Pac. Sci. Congress, Java, 437 (1919).

    Mida sect. Eucarya Kuntze in Post & Kuntze, Lex. Gen. Phan.: 367 (1903).

Semiparasitic trees or shrubs, twigs terete when young. Leaves mostly paired, rarely whorled; leaf blade ovate to lanceolate to linear. Inflorescence in axillary or terminal panicles. Flowers bisexual, 4- or 5-merous; hair clusters behind stamens; filaments short; glandular disk with triangular to lobed marginal extensions between petals; ovary semi-inferior or inferior; style slender, stigma 4-lobed; ovules 2–4, at lower end of elongated ovarian papilla. Fruit globular, nut-like, exocarp fairly thin, hard, wrinkled; germination (at least in S. album) cryptocotylar (Bhatnagar 1965). n=10, 20.

Nineteen spp., India, N and E Australia, SE New Guinea, and on numerous islands in the South Pacific, including Hawai’i (see Harbaugh and Baldwin 2007).

Santalum album, the original source of the distinctively fragrant sandalwood and sandal oil, is of controversial geographical origin (probably India), but has been commercially important for at least two thousand years. Hawaiian species were greatly exploited for the Chinese trade, and led to the rise of the local monarchy; consequently, some species have become very rare. For more details, see the introduction to Santalales. Mida fernandezianum, once regarded as a species of Santalum, is extinct on the Juan Fernández Islands after exploitation as a source of sandal oil, but occurs in New Zealand as M. salicifolia.

Santalum album has become locally established in Florida; it has also been introduced into Madagascar (Cavaco and Keraudren 1955).

  1. 32.

    Scleropyrum Arnott Fig. 60

    Fig. 60.
    figure 9

    Santalaceae. Scleropyrum wallichianum. A Twig. B Inflorescence. C Flower, one perianth segment removed. D Infructescence. (L.S.L. Chua 1996)

    Full size image

    Scleropyrum Arnott, Mag. Zool. Bot. 2: 549 (1838), nom. gen. conserv. # 2103.

Trees or shrubs, often with spines on trunks and branches, with simple hairs on leaves, young stems, and inflorescences. Leaves large, alternate, coriaceous. Inflorescence a spike with solitary flowers or small clusters of flowers at the nodes. Plants dioecious or polygamous. Inflorescence catkin-like, axillary, or racemose with short-pedicellate flowers; petals 4 or 5. Staminate flowers with 4 or 5 epipetalous stamens; filaments short; anthers with 4 locules, dehiscing with an oblique slit; post-staminal hairs present; aborted style small or lacking; glandular disk annular. Pistillate flower with inferior ovary; style short and thick; stigma broadly peltate, with dentate margin; ovarian cavity simple, with 3 ovules pendent from the tip of a straight funicular column. Fruit a large drupe, ellipsoid to pyriform, exocarp thick, fleshy, endocarp stony. Seed solitary, globular, embryo dicotylous.

About six closely related spp., Sri Lanka and India to New Guinea.

One of the earliest references to a species of this genus described it as parasitic (van Rheede tot Draakenstein 1636), but this cannot be regarded as a reliable observation, as also stated later by Arnott (1838). Ironically, 350 years later, it was nevertheless shown to be a root parasite by Nicolson et al. (1988).

  1. 33.

    Spirogardnera Stauffer

    Spirogardnera Stauffer, Vierteljahrsschr. Naturforsch. Gesellsch. Zürich 113: 305–309 (1968).

Small, glabrous, shrubby, sympodial root parasites with terete, rigid stems and alternate phyllotaxy. Juvenile leaves linear, early caducous, adult ones squamate. Inflorescence a terminal, mostly indeterminate spike of spirally arranged clusters of 3 or 4 flowers. Flowers bisexual, sessile, petals (4) 5, not articulated, cucullate, with post-staminal hairs; stamens as many as the petals and united with the base of the petals, filaments short; anthers dorsifixed, 2- or 4-loculate; glandular disk with conspicuous, truncate lobes alternating with the petals; ovary inferior; style very short, 5-lobed; ovarian cavity 5-chambered below, simple above; ovules 5, pendent from straight, central funiculus. Fruit a 1-seeded, sessile, ellipsoid drupe bearing the persistent, closed petals; exocarp thin, mesocarp fleshy, endocarp stony; embryo mostly dicotylous.

A single sp., Spirogardnera rubescens Stauffer, W Australia. This may instead be a species of Choretrum.

  1. 34.

    Staufferia Z.S. Rogers, Nickrent & Malécot

    Staufferia Z.S. Rogers, Nickrent & Malécot, Ann. Missouri Bot. Gard. 95: 394–398 (2008).

Trees or shrubs: Leaves alternate, estipulate, entire. Inflorescences axillary, the male thyrsoid, 4–10-flowered, bracteate, pistillate not seen. Dioecious. Petals 5, sessile; calyx absent, staminate flowers with 5 epipetalous stamens; anthers dorsi-basifixed; glandular disk stellate, lobes alternating with petals; sterile style present; ovary inferior, 1-locular; ovules 1–3, pendent from straight funiculus; style very short or absent; stigma subsessile, with 3–5 lobes. Fruit a drupe, obovoid, single-seeded; exocarp fleshy, 5-segmented, segments alternating with densely pubescent furrows; mesocarp stony, endocarp papery, very thin; endosperm copious.

One sp., Staufferia capuronii Z.S. Rogers, Nickrent & Malécot, endemic to Madagascar. Perhaps congeneric with Pilgerina.

It is possible that Staufferia is not dioecious, contrary to what the authors write, but that the flowers are bisexual. The authors have not seen the pistillate flowers, and do not indicate the sex of any of their illustrations. The “staminodes” in their Fig. K and L could be withered stamens, instead. This may indicate that Pilgerina and Staufferia should be united generically.

  1. 35.

    Thesidium Sonder

    Thesidium Sonder, Flora 40: 364 (1857).

Profusely branched, small shrubs or herbs with wooden base. Leaves alternate, mostly scale-like. Dioecious. Inflorescence a spike with numerous flowers, these solitary or in clusters of 3 in axillary positions to scale leaves, or in terminal spikes. Flowers 4(5)-merous, each with two prophylls, those of the pistillate more prominent than those of the staminate. Staminate flowers: petals with a cluster of hairs behind the stamens, the latter with short filaments; the style much reduced or absent. Pistillate flowers: ovary inferior, glandular disk not clearly delimited; ovules 2 or 3, suspended from the tip of a slender funiculus. Fruit a small nut bearing the persistent petals.

Seven spp., southwestern South Africa.

  1. 36.

    Thesium L.

    Thesium L., Sp. Pl.: 207 (1753).

    Austroamericium Hendrych (1963).

Perennial (rarely annual) herbs, some species rhizomatous, many African species with somewhat woody basal stems, or small shrubs. Leaves small, scale-like to mostly linear, alternate. Inflorescence a panicle, raceme or spike, or composed of 3- or more-flowered cymes, flowers bracteate, with or without prophyllar bracteoles. Flowers 4- or 5-merous, bisexual, gamopetalous, the receptacle sometimes elongated; petals sometimes hairy adaxially, or at least with a cluster of hairs behind (or on the back of) each stamen; filaments short, adherent to petal tube at its distal end; ovary inferior; ovules 2 or 3, pendent from the tip of a convoluted funiculus. Fruit a small nutlet with conspicuous surface venation, petals persistent. n = 6, 7, 8, 9, 12.

More than 240 spp. (perhaps the largest genus in Santalales), especially species-rich in arid South and Central Africa (including Madagascar), reaching N into Europe as far as Denmark; one sp. in SW Australia, and one introduced in Montana.