HABIT : seasonally dormant (A. americana), solitary herbs, rhizome hypogeal, erect. LEAVES : solitary, rarely 2. PETIOLE : unarmed, smooth to tubercular, geniculate apically. BLADE : pinnatifid and perforate or pinnatisect, juvenile leaves entire; basal ribs well-developed, primary lateral veins of ultimate lobes pinnate, higher order venation reticulate. INFLORESCENCE : solitary, rarely 2. PEDUNCLE : long, similar to petiole in colour and texture. SPATHE : membranaceous, papery when dry, marcescent, convolute basally, spirally twisted apically. SPADIX : stipitate, stipe mostly adnate to spathe, flowering sequence basipetal. FLOWERS : bisexual, perigoniate; tepals 4, fornicate. STAMENS : 4, filaments short, linear, connective slender, thecae dehiscing by short, apical pore-like slits. POLLEN : monosulcate, ellipsoid, medium-sized (31 µm.), exine foveolate, apertural exine psilate. GYNOECIUM : ovary 1-locular, ovules 1-2, anatropous, placenta basal, style ± attenuate, stigma subcapitate. BERRY : ovoid to obpyramidal, reddish. SEED : campylotropous, testa thick, verruculose to channelled, embryo curved, endosperm present.
Seasonally dormant, solitary helophytes with erect hypogeal rhizome; petiole unarmed, smooth to tuberculate, geniculate apically; spathe twisted apically; flowers bisexual, perigoniate. Differs from palaeotropical Anaphyllum in having seeds with a thick, verrucose testa and a curved embryo and in its neotropical range.