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GrassBase - The Online World Grass Flora
Descriptions
W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson
© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.
Rottboellia purpurascens
HABIT Annual. Culms robust; 100–160 cm long; with prop roots. Culm-nodes pubescent. Leaf-sheaths pilose; with tubercle-based hairs. Ligule an eciliate membrane. Leaf-blades 25–55 cm long; 4–19 mm wide. Leaf-blade margins scabrous. Leaf-blade apex attenuate.
INFLORESCENCE Inflorescence composed of racemes; terminal and axillary; subtended by an inflated leaf-sheath. Peduncle widened at apex.
Racemes 1; single; unilateral; 4–13 cm long. Rhachis fragile at the nodes; subcylindrical and excavated; 5 mm wide; glabrous on margins. Spikelet packing abaxial; regular. Rhachis internodes oblong; 2.5–4 mm long. Rhachis internode tip transverse; crateriform; with simple rim.
Spikelets sunken; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels fused to internode; united below; oblong; flattened.
STERILE SPIKELETS Companion sterile spikelets well-developed; male; ovate to cuneate; dorsally compressed; 3–5 mm long; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; smooth; glabrous; acute; muticous. Companion sterile spikelet lemmas enclosed by glumes.
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; gibbous; 3–4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous; base truncate; with central boss; attached transversely.
GLUMES Glumes dissimilar; reaching apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; indurate; 2-keeled; winged on keel; winged narrowly; winged above; 12–16 -veined. Lower glume apex emarginate. Upper glume ovate; chartaceous; 1-keeled; winged on keel; winged above. Upper glume apex acute.
FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret ovate; 3.5 mm long; hyaline; 3 -veined; acute. Palea of lower sterile floret 0.5 length of lemma. Fertile lemma ovate; 3.5 mm long; hyaline; 1 -veined. Lemma apex acute. Palea 0.5 length of lemma; hyaline; without keels.
FLOWER Anthers 3.
DISTRIBUTION Africa: west tropical, west-central tropical, and southern tropical.
NOTES Andropogoneae. FWTA.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
