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 heteromorpha

HABIT Annual. Culms 20–35 cm long; 6–9 -noded. Lateral branches ample. Leaf-sheaths 0.8–1.5 cm long; pilose. Ligule a ciliolate membrane. Leaf-blades straight, or curved; flat, or involute; 1.5–8 cm long; 1–2 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; widened at apex; disarticulating; disarticulating above uppermost sheath; base pungent.

Racemes 1; single; smoothly terete; unilateral; 1–2 cm long; bearing 2–8 fertile spikelets on each, or 5–6 fertile spikelets on each (heteromorphic). Rhachis fragile but the lowest internode fused to peduncle; subcylindrical and excavated; 0.5 mm wide, or 1–1.5 mm wide; terminating in a sterile spikelet. Spikelet packing abaxial; regular; 1 -rowed, or 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; 2.5–3 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; 5–7 -veined. Lower glume surface convex, or flat; smooth, or areolate. 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.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. Simon 1994.

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