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.

Thaumastochloa pubescens

HABIT Annual. Culms 12–30 cm long; 5–9 -noded. Leaf-sheaths pilose. Ligule a ciliolate membrane. Leaf-blades 2–9 cm long; 1.5–4 mm wide. Leaf-blade surface pilose.

INFLORESCENCE Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole linear. Peduncle straight; 5–10 cm long; retrorsely scabrous above; widened at apex; disarticulating; disarticulating above uppermost sheath; base pungent.

Racemes 1; single; smoothly terete; unilateral; 1.5–3.5 cm long; bearing 4–9 fertile spikelets on each. Rhachis fragile but the lowest internode fused to peduncle; subcylindrical and excavated; 1–1.8 mm wide; glabrous on surface, or puberulous on surface; terminating in a sterile spikelet. Spikelet packing abaxial; regular; 2 -rowed. Rhachis internodes oblong; 3–4 mm long. Rhachis internode tip transverse, or oblique; crateriform.

Spikelets sunken; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels fused to internode; united wholly.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.

Apical sterile spikelets rudimentary.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 2–3 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous; base truncate; with central peg; attached transversely, or attached obliquely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume ovate; 1 length of spikelet; indurate; 2-keeled; keeled laterally; 7–9 -veined. Lower glume surface convex, or flat; smooth, or cancellate. Lower glume apex acute. Upper glume elliptic; coriaceous; with hyaline margins; without keels.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret hyaline. Fertile lemma hyaline; without keel; 2 -veined. Palea hyaline.

FLOWER Anthers 3; 0.75–1 mm long.

DISTRIBUTION Asia-tropical: Papuasia. Australasia: Australia.

NOTES Andropogoneae. Koning.

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