Terrestrial rhizomatous herbs, sometimes lianescent and high-climbing, very variable in development of aerial shoots. Leaves distichous, segregated into sheath, petiole proper (often missing), pulvinus and blade; blade with a strong midrib and thin, parallel and closely set lateral veins, these ± sigmoid, fusing marginally, interconnected by closely set, parallel transverse veinlets. Inflorescence terminal or lateral, simple or a ± complex synflorescence; inflorescence unit (florescence) or usually spiciform or capitate thyrse with distichous or spiral spathes (bracts) subtending ± elaborate flower clusters composed of I-several (rarely numerous) 2-flowered cymules (1-flowered in Monotagma and Monophrynium), each with a prophyll on the dorsal side at base, sometimes also with a scale-like interphyll on the ventral side and 1 or 2 ± dorsal bracteoles (additional lateral bracteoles in one species of Calathea). Flowers perfect, epigynous, pentacyclic, heterochlamydeous, completely asymmetric (the 2 flowers of a pair being mirror images); sepals distinct; petals, androecial elements, and style fused to form a floral tube (corolla tube) greatly variable in length. Outer androecial whorl rarely missing, usually of 1 or 2 staminodes, which are usually petaloid and showy, but sometimes acicular, or ± rudimentary; inner androecial whorl of 3 members, 1 fertile monothecic stamen (often with a petaloid appendage), 1 hood-shaped staminode (staminodium cucullatum), and 1 conspicuously firm and fleshy staminode (staminodium callosum); the inner staminodes basally fused to form a firm and fleshy staminal tube which ± exceeds the level where the corolla lobes separate from the floral tube. Ovary 3-carpellate and 3-locular, but 2 locules often empty and compressed; fertile locule(s) I-ovulate with the anatropous ovule inserted at base; septa with completely sunken septal nectaries. Style fused basally with the floral tube, in mature untriggered flowers the style enclosed in the hood of the cucullate staminode, bent backwards and held under tension; when released by a pollinator, snapping forward and curling up in a circinate or (Thalia) helical fashion; stigmatic surface restricted to the inner side of a funnel-shaped depression in the apex of the style. Fruit usually a loculicidal capsule, more rarely berry-like (Sarcophrynium, Thaumatococcus), or caryopsislike (Thalia). Seeds rather large (3-20mm), without endosperm at maturity, embryo horseshoe-shaped, embedded in copious starchy perisperm; perisperm with a simple or forked, central canal running from base to the level of the embryo bend, or slightly further.
Andersson, L., Kubitzki, K., 1998. Marantaceae With kind permission from Springer Science+Business Media: This work is subject to copyright. All rights reserved, whether whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, broadcasting reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under German Copyright Law.