GrassBase - The Online World Grass Flora


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

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

Themeda arguens

HABIT Annual; caespitose. Culms erect; 20–120 cm long. Leaves mostly basal. Ligule an eciliate membrane; 1 mm long. Leaf-blade base broadly rounded. Leaf-blades flat, or conduplicate; 5–30 cm long; 4–7 mm wide. Leaf-blade apex acuminate.

INFLORESCENCE Synflorescence compound; fasciculate. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole lanceolate; 2.5–3.5 cm long; scarious; without tubercles; glabrous.

Racemes 1; single; cuneate; bearing few fertile spikelets; bearing 1 fertile spikelets on each. Rhachis fragile at the nodes.

Spikelets in threes (basal paired). Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels oblong; 1 mm long; tip oblique.

STERILE SPIKELETS Basal sterile spikelets represented by a single scale; 4 in number; forming an involucre about the fertile; with both pairs arising at about the same level; subsessile; 6–10 mm long; equalling fertile. Basal sterile spikelet glumes smooth; glabrous; lower glume muticous.

Companion sterile spikelets well-developed; comprising 2 subequal glumes without lemmas; lanceolate; 6 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet callus linear; 2–3 mm long; truncate. Companion sterile spikelet glumes herbaceous; glabrous; acuminate.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; subterete; 8–10 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus linear; 3 mm long; bearded; base pungent; attached obliquely. Spikelet callus hairs red.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; dark brown; without keels; 7 -veined. Lower glume surface pilose; hairy above. Lower glume hairs dark brown. Lower glume apex truncate. Upper glume oblong; coriaceous; with membranous margins; 3 -veined. Upper glume surface pilose; hairy above. Upper glume margins ciliate. Upper glume hairs dark brown. Upper glume apex truncate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 2.8 mm long; hyaline; ciliate on margins. Fertile lemma oblong; 3 mm long; hyaline; without keel; 1 -veined. Lemma apex entire; awned; 1 -awned. Principal lemma awn apical; geniculate; 50–70 mm long overall; with twisted column. Column of lemma awn hispidulous. Palea absent or minute.

FLOWER Anthers 1.4 mm long.

DISTRIBUTION Asia-temperate: China. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern. South America: Caribbean.

NOTES Andropogoneae. Gilliland 1993.

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