Monographs Details: Renealmia
Maas, Paulus J. M. 1977. Renealmia (Zingiberaceae--Zingiberoideae), Costoideae (Additions) (Zingiberaceae). Fl. Neotrop. Monogr. 18: 1-218. (Published by NYBG Press
Synonyms:Pacoseroca Marcgr., Alpinia, Amomum, Ethanium Salisb., Gethyra Salisb., Peperidium Lindl., Siphotria
Description:Description - Tall to low, unbranched, aromatic, perennial herbs with sympodial, subterranean rhizomes. Leaves distichous. Leaf-sheaths open, striate, reticulate, or sometimes smooth, in nearly all species covered with prickle-like hairs (less than 0.1 mm long). Petiole small to long, sometimes absent. Ligule truncate, usually very small. Lamina more or less narrowly elliptic in outline, its base cuneate, the apex acuminate to acute, mostly superficially glabrous, but the lower side nearly always covered with microscopic hairs. Inflorescence a thyrse, raceme, or very rarely a spike, terminating a separate leafless shoot and its scape provided with leafless sheaths (cataphylls), sometimes terminal on a leafy shoot. Indument of inflorescence: nearly always present and composed of simple, furcate, or plurifurcate, one-celled hairs (stellate, irregularly branched hairs and compass-needle hairs rare). Bracts herbaceous to membranous, persistent, often soon deciduous, rarely chartaceous to coriaceous; bracts subtending one flower (racemose species) or cincinni of 2-10(-17) flowers (thyrsoid species). Basal stalk of cincinni (=peduncle) and pedicels small to relatively long. Bracteole herbaceous, tubular and closed before anthesis, or in some species cup-shaped and open even before anthesis. Calyx tubular, turbinate, or less often urceolate, persistent or rarely deciduous, the 3 lobes deflate to triangular. Corolla tubular at the base, the tube somewhat longer than the calyx, the 3 lobes imbricate in bud, narrowly elliptic, the dorsal one somewhat larger than the 2 lateral ones. Labellum: basal part (=basal claw) narrowed, often hairy,with 2 very small, toothlike, lateral staminodes; apical part (=limb) composed of two rounded lateral lobes and a middle lobe with an entire to two-lobed apex; lateral lobes involute (tubular flower) or horizontally spreading (gullet flower). Stamen one, with a very small filament (ca 1 mm long) and a dithecic, yellow to red anther. Style filiform, enclosed between the two thecae. Stigma cup-shaped placed at the top of the anther. Nectarial glands implanted at the top of the ovary, partly or completely surrounding the style base. Ovary trilocular, ellipsoid to globose, ovules few-00, biseriate. Capsule often black or red, trilocular, globose to ellipsoid, more or less fleshy, mostly crowned by the persistent calyx, longitudinally loculicidally dehiscent from base to apex; seeds 1-250, glossy brown, more or less irregularly ellipsoid, provided with a large, yellow to orange or white (sometimes sweet) aril. Chromosome number 2n = 22 or 44.