Families of Flowering Plants of Australia

Stemonaceae

This small family is restricted to south-east Asia from India and southern China to New Guinea and northern Australia, in woodlands, monsoon forests and rainforest margins.

Characteristic features of the family Stemonaceae in Australia include:

herbs with twining or prostrate stems to several metres long with alternate, narrowly to broadly ovate leaves with parallel veins and prominent, finer cross-veins
flowers bisexual, regular, with 4 petal-like perianth segments and 4 stamens with rather broad, petaloid filaments, the connective extending well above the anther
ovary superior, 1-carpellate, developing into a 2-valved capsule

Description

Herbaceous vines climbing by twining or scrambling stems, or perennial terrestrial herbs. Perennating by rhizomes. Internal secretions not obvious. Plants glabrous. Leaves alternate and spiral, or distichous, or opposite, cauline, petiolate. Stipule-like lobes absent. Lamina simple, symmetric, filiform, acicular, subulate, linear, lanceolate, ovate, elliptic or oblong; base cuneate, cordate or hastate or sagittate; margins entire, ±flat; venation parallel, with the midrib conspicuous, and the tertiary venation reticulate; surfaces not punctate; herbaceous. Leaf ligule absent. All the flowers bisexual. Inflorescences axillary, consisting of dichasial cymes or solitary flowers. Bracts present. Pollination by insects. Flowers odourless or malodorous, stalked. Floral disc present or absent; nectaries absent. Perianth regular, of 2 ±similar whorls, with 4 free or fused, ±petaloid segments, valvate in bud, cream, red, purple, grey, brown or black, without contrasting markings, membranous or herbaceous; claws absent; lobes ±entire. Fertile stamens 4, alternating with or opposite to and at least partly fused to the perianth segments, free of the ovary and style, distinct from each other, or fused by their filaments into an open or closed tube, all ±equal. Anthers basifixed, not versatile, opening sideways by longitudinal slits, 2-celled; appendages apical. Ovary superior and sessile. Carpel 1; ovary with 1 locule. Style terminal, single and unbranched, or absent and the stigma ±sessile. Ovules 2–8, stalked; placentation basal. Fruit a dry, dehiscent, bi-valved capsule; the perianth on the maturing fruit deciduous. Disseminule micro-surface finely striate-costellate, dull. Seeds 1–8 per fruit. Aril present. Cotyledons 1.

(Note: this description has been generated from the coded data compiled for the key. Any errors in the key data will be reflected in the descriptions.)

A treatment of the family Stemonaceae has been published in:
Flora of Australia 46: 177-180.

Australian genera of Stemonaceae (as recognised for the Flora of Australia)

Stemona