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.

Rottboellia coelorachis

HABIT Annual. Culms 150–200 cm long. Ligule an eciliate membrane. Leaf-blade base broadly rounded. Leaf-blades lanceolate; 15–30 cm long; 25–35 mm wide. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes; terminal and axillary; subtended by an inflated leaf-sheath. Peduncle widened at apex.

Racemes 1; single; smoothly terete; unilateral; 10–16 cm long. Rhachis fragile at the nodes; subcylindrical and excavated; glabrous on margins; terminating in a sterile spikelet. Spikelet packing abaxial; regular. Rhachis internodes oblong; 7–9 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 wholly; columnar; flattened; 5–7 mm long.

STERILE SPIKELETS Companion sterile spikelets rudimentary, or well-developed; containing empty lemmas; ovate; dorsally compressed; 1–6 mm long; deciduous with the fertile. Companion sterile spikelet glumes chartaceous, or coriaceous; smooth; glabrous; obtuse; 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; 5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous; base truncate; with central peg; attached transversely.

GLUMES Glumes dissimilar; reaching apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; indurate; 2-keeled. Lower glume apex obtuse. Upper glume ovate; chartaceous; 1-keeled. Upper glume apex acute.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret ovate; hyaline; acute. Fertile lemma ovate; hyaline; 1 -veined. Lemma apex acute. Palea hyaline; without keels.

FLOWER Anthers 3.

DISTRIBUTION Australasia: Australia. Pacific: southwestern.

NOTES Andropogoneae. WDC.

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