HABIT : climbing herbs. LEAVES : distichous. PETIOLE : geniculate apically, sheathed nearly to apex, sheath persistent or marcescent. BLADE : obliquely ovate-oblong, entire; primary lateral veins pinnate, running into marginal vein, higher order venation reticulate. INFLORESCENCE : 1-3 in each floral sympodium. PEDUNCLE : relatively long. SPATHE : oblong-ovate, boat-shaped to reflexed, greenish white, rostrate apically and overtopping the spadix, deciduous after anthesis. SPADIX : stipitate, cylindric. FLOWERS : bisexual, perigoniate; perigone membranaceous, a single cup-like structure, truncate, equalling or shorter than gynoecium. STAMENS : 4, filaments relatively short, broad, spathulate, connective slender, thecae linear-elliptic, dehiscing by longitudinal slit. POLLEN : inaperturate, subspheroidal, small (mean 22 µm.), exine psilate or subretipilate, pilae spinulose tipped and solitary, or united into groups of 2-4 or more. GYNOECIUM : ovary obconic or obpyramidal, subquadrangular, 1-locular, ovule 1, anatropous, funicle short, placenta basal, stylar region as broad as ovary, stigma transversely oblong. BERRIES : distinctly truncate apically, subglobose, orange red (A. microstachyum). SEED : rounded, subglobose, testa smooth, glossy, embryo large, endosperm absent.