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FOC | Family List | FOC Vol. 22 | Poaceae

223. Coix Linnaeus, Sp. Pl. 2: 972. 1753.

薏苡属 yi yi shu

Authors: Shou-liang Chen & Sylvia M. Phillips

Annual or perennial. Culms robust, erect or decumbent, sometimes floating, usually solid. Leaves cauline; leaf blades large, usually broad, flat; ligule membranous. Inflorescences many, fascicled in the upper leaf axils, each subtended by a globose or elongated, bony or sometimes softer modified involucral spatheole ("utricle"); each inflorescence comprising 2 racemes, a female sessile raceme enclosed within the utricle, and a pedunculate male raceme subtended by a prophyll and exserted from the apical pore of the utricle. Female raceme of 1 sessile fertile spikelet accompanied by 2 free stout pedicels, sometimes bearing vestigial spikelets. Female spikelet: lower glume broad, infolding spikelet, membranous with cartilaginous beak; upper glume narrower, keeled; lower floret reduced to a broad hyaline lemma; upper floret with hyaline lemma and palea; lodicules absent; stigmas 2, elongate, exserted from utricle. Male raceme deciduous at maturity, composed of imbricate spikelets borne in pairs or triads, 1(–2) sessile and 1 pedicelled, pedicelled spikelet often reduced in triads. Male spikelets: glumes subequal, herbaceous; lower glume flat on back, margins keeled, keels winged upward, wings with obvious branching veins; upper glume boat-shaped; both florets staminate, lemma and palea hyaline. Caryopsis orbicular, ventrally furrowed, enclosed in utricle.

Four species: tropical Asia; two species in China.

1 Annual, culms tufted; leaf blades 1.5–7 cm wide, acute; male spikelets mostly paired (except terminal triad).   1 C. lacryma-jobi
+ Perennial, culms often decumbent and rooting at base; leaf blades 0.3–2.5 cm wide, slenderly acuminate; male spikelets in triads   2 C. aquatica

Lower Taxa


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