Scandent shrubs (often erect in youth), without resin; branches sympodial with a series of circinate woody hooks in one plane. Leaves spread, simple, entire, often rosette-crowded, cuneiform, penninervous, reticulate-veined, glabrous, both surfaces minutely pitted, each pit with a peltate small hair secreting a waxlike substance; petiole articulated, scar on the twigs often saddle-shaped; stipules absent. Flowers bisexual, actinomorphic small. Inflorescences few or several times dichotomous or spike-like, often provided with said hooks and single reduced bract-like leaves, branches often recurved. Pedicels articulated. Bracts with a glandular-thickened base, margin fimbriate-membranous. Calyx tube short, at length adnate to the base of the ovary; lobes 5 inequal imbricate, enlarged and wing-like in fruit. Petals 5, united at the base, slightly contorted in bud. Stamens mostly 10, rarely 5, the episepalous slightly longer. Filaments with broadened base; anthers basifixed, ± introrse to ± latrorse, 2-celled, opening lengthwise. Ovary for the greater part inferior, consisting of 3 carpels, 1-celled, protruding into a nipple-shaped elongation bearing 3 articulated erect styles with a punctiform or horseshoe-shaped stigmatic apex; nipple enlarging in fruit. Ovule 1, basal, ascending, with 2 integuments. Nut not dehiscent, crowned by the enlarged calyx. Seed roundish with testa intruding between the cerebral-like folds of the endosperm. Exocarp leathery. Embryo straight, erect, obliquely placed; cotyledons diverging; hypo-cotyl rather thick.
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Morphological characters and geographic distribution are the same as those of the family.
Characters of the family.
In mixed rain forests, but most common on silicious soil in so-called 'padang-scrub', from the lowland to the hills. KERR noted of A. wallichii (his no 7006) that all specimens grew erect, and it is reported by GAGNEPAIN to be erect in youth. RIDLEY also found it on the ground as a bush, or ascending trees, and this is also observed in specimens from Sumatra and Borneo. In the open padang-scrub it is either erect or trailing.