Cyclanthaceae

Abstract

Monoecious, perennial, terrestrial or sometimes epiphytic herbs, or herbaceous vines or lianas. Stem very short to long and slender, unbranched or branched, rhizomatous to aerial, usually ± lignified. Leaves spiral, spirodistichous, or orthodistichous; adult leaves always with leaf sheaths, petiolate in most species; leaf blades generally bifid, more seldom flabelliform-parted or entire, unicostate or tricostate. Inflorescence an axillary or terminal, unbranched, pedunculate spadix subtended and initially enveloped by 2–11 conspicuous, foliaceous or petalaceous spathes. Flowers unisexual, densely crowded, generally (subfam. Carludovicoideae) in spirally arranged groups (partial inflorescences), each group consisting of 1 pistillate flower surrounded by 4 staminate flowers, or (subfam. Cyclanthoideae) in alternate cycles, seldom spirals, of staminate and pistillate units. Staminate flowers in the Carludovicoideae usually with marginally situated perianth lobes on abaxial side to all around the receptacle, lobes usually in 1 whorl, rarely in 2 whorls or lacking; staminate flowers in the Cyclanthoideae as linear rows of stamens; stamens mostly numerous; anthers basifixed, bithecate and tetrasporangiate, usually longitudinally dehiscent, rarely with a special 2-phase dehiscence mechanism; filaments basally ± connate and usually swollen into so-called basal bulbs, filaments or basal bulbs rarely lacking. Pistillate flowers in the Carludovicoideae free or usually partly connate with each other; tepals 4, free or connate, usually epigynous to perigynous, more seldom almost hypogynous, of different shape, often enlarged and indurate in fruit; staminodes 4, flexuously filiform, opposite the tepals; ovary 4-carpellate, unilocular, entirely protruding from or more often ± embedded in the rachis, with 4 parietal, subapical, or apical placentae, or with one apical placenta, each placenta bearing numerous anatropous, heterotropous ovules; styles lacking or 4 free styluli, or these ± concrescent into a common style; stigmas 4, alternating with the tepals, of different shape; styluli and stigmas generally persisting and enlarging during fruit development; pistillate flowers in the Cyclanthoideae not discernible, coalescent into cycles (rarely spirals) consisting of double pistillate rows with locules confluent into a continuous ovarian chamber with numerous parietal placentae, each pistillate row having 1 row each of very much reduced perianth, staminodes, and carpels. Fruits in the Carludovicoideae ± fleshy, free or united to a syncarp; in the Cyclanthoideae united to ± dry, hollow rings (or spirals) filled with seeds. Seeds numerous, small to rather large, flat to terete; testa variable; endosperm copious, fat and fleshy, usually lacking starch; embryo medium-sized, straight.