Araceae

Abstract

Herbs, diminutive to gigantic, terrestrial, geophytic, epiphytic, or climbing, rarely aquatic; with true or false stems; tissues with raphides; laticifers commonly present; mature shoots composed of articles forming a sympodium (except Pothoideae, Heteropsis); leaf bifacial, usually differentiated into petiole and expanded blade of very variable shape; midrib compound; primary venation usually pinnate but sometimes pedate or arcuate from the base or strictly parallel, fine venation ± reticulated or parallel-pinnate (i.e. parallel to primary lateral veins); inflorescences 1-many, each inflorescence a pseudanthium (especially so when flowers unisexual) consisting of a spadix (a dense spike of minute, ebracteate flowers) subtended by a spathe (last leaf of article, usually specialised in form and colour, inconspicuous in Gymnostachys, Orontium); flowers sessile (except Pedicellarum), bisexual or unisexual (unisexual inflorescences in Arisaema — paradioecy), when unisexual the female flowers occupying the proximal part and males the median or distal part of the spadix; perigone present or absent, tepals free, partly or completely connate; stamens usually 3 + 3 or 2 + 2, or sometimes less or more, opposite tepals in bisexual flowers, free to connate, anthers extrorse (except Zamioculcas, Pedicellarum); gynoecium syncarpous, ovary usually 1–3 locular (1–8 locular in Spathicarpeae, 2–47-locular in Philodendron), ovules bitegmic, atropous, anatropous, anacampylotropous or of intermediate form; style usually inconspicuous, stigma wet at anthesis, sometimes distinctly lobed; fruit a berry (basally dehiscent in Lagenandra), usually free and borne in ± cylindric, dense, fleshy spike, rarely connate into syncarp; seeds small to very large, testa very thin to very thick, rarely absent, endosperm present or absent, embryo minute to large, both with or without starch, chlorophyllous or not.