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.

Thaumastochloa major

HABIT Annual. Culms geniculately ascending, or decumbent; 15–35 cm long; 6–9 -noded; rooting from lower nodes. Culm-nodes bearded. Ligule a ciliolate membrane; 0.3 mm long. Leaf-blades 4–12 cm long; 3–5.5 mm wide. Leaf-blade margins cartilaginous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole linear; 2.5–4 cm long; herbaceous. Peduncle nodding; retrorsely scabrous above; widened at apex; disarticulating; disarticulating above uppermost sheath; base pungent.

Racemes 1; single; unilateral; 2.5–4 cm long; bearing 3–10 fertile spikelets on each. Rhachis fragile but the lowest internode fused to peduncle; subcylindrical and excavated; 2.7–3.1 mm wide; terminating in a sterile spikelet. Spikelet packing abaxial; regular; 2 -rowed. Rhachis internodes oblong; 4.2–6.5 mm long. Rhachis internode tip 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; 2–3 in number.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 2.6–3.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base truncate; with central boss; attached obliquely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume ovate; 2.6–3.5 mm long; 1 length of spikelet; indurate; 2-keeled; keeled laterally; 9–10 -veined. Lower glume apex obtuse. Upper glume elliptic; coriaceous; with hyaline margins; without keels; 5 -veined. Upper glume margins ciliolate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret ovate; 2.5–2.75 mm long; hyaline; 2 -veined; ciliolate on margins; obtuse. Fertile lemma ovate; 2.2–2.7 mm long; hyaline; without keel; 0–2 -veined. Lemma margins ciliolate; hairy above. Lemma apex obtuse. Palea oblong; 0.9 length of lemma; 0–2 -veined; without keels.

FLOWER Anthers 3; 0.9–1 mm long.

FRUIT Caryopsis with adherent pericarp; ovoid; 2.3 mm long.

DISTRIBUTION Asia-tropical: Malesia and Papuasia. Australasia: Australia.

NOTES Andropogoneae. WDC.

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