Phthirusa pyrifolia (Kunth) Eichler

Global description

Phthirusa pyrifolia is a woody epiphytic hemiparasitic plant up to 1 m long, which develops on the branches of host trees. A sucker is inserted into the tissues of the branch. The roots grow around the bearing branch. The stems are scaly, brown (furfuraceous) with green and smooth areas. Leaves are simple, opposite, short-petiolated with oval lamina, fleshy, shiny green. Inflorescenses are axillary solitary long spikes with brown axis. Flowers arranged in 5 to 20 pairs of opposite triads, spaced from each other. Twisting flowers. The fruit is an elliptical berry turning orange.

Cotyledons

The seed deposited on a branch of tree germinates and emits a sucker (haustorium) cylindrical, 0,5 cm long, of green color, widened in button at its end. It penetrates the bark and attaches to the vessels of the xylem where vascular contact will allow the parasitic plant to feed. At the top of this axis are two linear to elliptic cotyledons, 2 cm long and 0.5 cm wide, with rounded or acute apex and slightly attenuated base. They are thick, slightly fleshy and bright green in color.

First leaves

The first leaves are simple, opposite, subsessile, linear to lanceolate, fleshy, bright green in color. The margin is entire, the apex is acute and the base attenuated. The central rib is just visible.

General habit

Phthirusa pyrifolia is an erect epiphytic hemiparasitic plant that grows on the branches of trees. The axis can become abundantly branched and reach 1m long.

Root

The roots develop only at the base of the parasitic plant, just above the sucker (haustorium). They are quickly woody, epicortical and enclose the branch of the host tree in a network that quickly becomes strangler. The older roots have a furfurate epidermis, covered with streaks of brown scales, giving a rough appearance.

Stem

The stem is quickly woody, slightly flattened (especially when young) or cylindrical, solid. It can measure 0.5 to 2 cm in diameter especially below the nodes. The epidermis of the young stems is glabrous, smooth and bright green in color. In aging it becomes rough, furfuraceous, covered with brown scales. The main axis can be single or branch quickly.

Leaf

The leaves are simple, opposite, borne by a short petiole 1 to 2 cm long, more or less winged by the base of the lamina decurrent along the petiole. For older leaves, it is partially furfurate (covered with brown scales), leaving shiny green areas at the edges and at the tip. The blade is entire, thick to coriaceous, glabrous, bright green in color, becoming dark green as it ages. It is widely lanceolate, or oval elliptical, and is 10 to 18 cm long and 4 to 6 cm wide. The apex is rounded to acuminate, sometimes slightly emarginate and mucronate, the base is obtuse to truncate, the margin is entire. The venation is pinnate.

Inflorescence

Inflorescences are large loose spikes, usually solitary at the axil of the leaves (never in terminal groups). They are formed by a cylindrical, erect, 6- to 15-cm long, furfuraceous woody axis bearing 8 to 20 opposite pairs of flower triads (flowers in groups of three). The pairs of floral triads are clearly distant from each other. The triads are subsessile to very short pedunculate.

Flower

The flowers are sessile, presenting at their base a green fleshy truncated calyx formed of 2 troncated prophyls, The tepals are vinous red to pale red, 15 mm long, oblong and pointed. The stamens, shorter than the tepals, are sessile fused with the lower half of the tepal, anther as wide as long and fleshy. The ovary is red, with sessile stigma. Presence of prominent nectar producing abundant nectar.

Fruit

The fruit is an oblong berry 8 mm long and 5 mm in diameter becoming yellow to orange at maturity, then gray to brown when drying. The tegument is tough, the pulpit is white and sticky. It contains only one seed.

Seed

The seed is ellipsoid 5 mm long, yellow in color, finely striated longitudinally and ending in a small pointed tip.

Origine

Phthirusa pyrifolia is native to tropical regions of Central America and South America

Worldwide distribution

This species is present in French Guiana, Surinam and Guyana, in Belize, in Peru, in Bolivia, in Brazil, in Panama, in Mexico (Chiapas), in Jamaica.

https://www.gbif.org/fr/species/7288052