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Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Hyparrhenia violascens

HABIT Annual; caespitose. Butt sheaths glabrous. Culms erect; 50–100 cm long. Leaves cauline. Ligule an eciliate membrane; 1 mm long. Collar glabrous, or pubescent. Leaf-blades 20–40 cm long; 3–6 mm wide.

INFLORESCENCE Synflorescence compound; scanty; 20–30 cm long. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; exserted. Spatheole linear; 4–7 cm long; membranous. Peduncle flexuous; pilose above.

Racemes 2; paired; deflexed, or spreading; 1.5–3 cm long; bearing few fertile spikelets; bearing 3–5 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs white. Rhachis internodes linear. Rhachis internode tip oblique; flat. Raceme-bases filiform; unequal (the longer measured); 2–3 mm long; glabrous, or pubescent (foot glabrous).

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; flattened; ciliate; tip oblique; toothed (0.3–0.7mm).

STERILE SPIKELETS Basal sterile spikelets well-developed; 2 in number (lower raceme); 0 in upper raceme; lanceolate; 7–8 mm long; larger than fertile. Basal sterile spikelet glumes pubescent; with white hairs, or dark brown hairs; smooth on margins; lower glume muticous.

Companion sterile spikelets well-developed; containing empty lemmas, or male; linear, or lanceolate; dorsally compressed; 6–7 mm long; longer than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; pubescent; with white hairs, or yellow hairs; acute, or acuminate; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear, or lanceolate; dorsally compressed; 5–6.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus linear; 0.8–1.2 mm long; pubescent; base acute; attached obliquely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; without keels; keel-less except near apex. Lower glume surface pubescent to villous. Lower glume hairs white. Lower glume apex dentate; 2 -fid. Upper glume linear; coriaceous; without keels.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 1 length of fertile lemma; hyaline; 2 -veined. Fertile lemma linear; membranous; without keel; 1 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 25–40 mm long overall; with twisted column. Column of lemma awn pubescent (white or fulvous); with 0.1–0.5 mm long hairs. Palea absent or minute.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3. Stigmas 2.

DISTRIBUTION Africa: west tropical, west-central tropical, and northeast tropical.

NOTES Andropogoneae. WDC.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.