Heliconiaceae

Abstract

Rhizomatous herbs, often very tall. Aerial stems either very short and leaf sheaths then forming a pseudostem, or elongate with distinct internodes, tightly enveloped by leaf sheaths; buds axillary. Leaves distichous, differentiated into sheath, petiole (sometimes indistinct or lacking) and blade; sheath without distinct ligule; blade entire, with coarse midrib and closely set, parallel, slightly sigmoid lateral veins fusing near margin; lateral veins interconnected by tertiary cross-veins. Inflorescence terminal, usually on leafy shoots but sometimes on specialized shoots bearing only bladeless sheaths, thyrsiform, bearing cincinnate flower clusters in axils of spathaceous bracts on an indeterminate main axis. Flowers subtended by carinate bracteoles, perfect, trimerous and 5-cyclic, heterochlamydeous; perianth zygomorphic, all elements fused to form a basal tube, lateral sepals and petals fused above tube, median sepal free; androecial elements six, the outer median stamen staminodial, scalelike, inserted on top of the basal perianth tube opposite the median sepal, the remaining 5 stamens fertile, with filaments adnate to the tubular part of the perianth, anthers basifixed, elongate, 2-thecate, 4-sporangiate. Ovary inferior, 3-locular; placentation axile; ovules anatropous, subbasal and single in each locule; style 1, filiform, stigma capitate. Septal nectaries present. Fruit drupaceous with 3 operculate pyrenes; seeds exarillate, with thin aleurone-storing perisperm and copious, starch-and oil-storing endosperm.