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.

Ischaemum australe

HABIT Perennial; caespitose. Rhizomes short. Culms erect; 50–150 cm long; 4–5 -noded. Culm-nodes pubescent. Lateral branches lacking. Leaf-sheaths 10–15 cm long; glabrous on surface. Ligule a ciliolate membrane; 3 mm long. Leaf-blades 10–20 cm long; 3–5 mm wide. Leaf-blade surface glabrous.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2; paired; appressed back to back; 3–10 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes oblong; 3–6 mm long; flat and forming a U or V shape with the pedicel in rear view. Rhachis internode tip transverse; cupuliform.

Spikelets in pairs. Fertile spikelets sessile to sessile and pedicelled; 1 in the cluster, or 2 in the cluster. Companion sterile spikelets pedicelled; 0–1 in the cluster. Pedicels oblong; 0.7–0.8 length of internode; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; asymmetrical; laterally compressed; 6–7 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; winged on keels. Companion sterile spikelet lemmas 2; enclosed by glumes; entire; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 6–7 mm long; falling entire; deciduous from the base, or with accessory branch structures. Spikelet callus base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; asymmetrical; 1 length of spikelet; chartaceous; 2-keeled; keeled all along; keeled laterally; winged on keel; winged narrowly. Lower glume primary vein ciliolate. Lower glume surface flat. Lower glume apex acute. Upper glume lanceolate; chartaceous; 1-keeled; winged on keel; 7 -veined. Upper glume margins ciliolate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; membranous; 3 -veined; ciliate on margins; acute. Fertile lemma oblong; membranous; without keel. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; curved; 8–10 mm long overall.

FLOWER Anthers 3; 3–5 mm long.

DISTRIBUTION Asia-tropical: Indo-China, Malesia, and Papuasia. Australasia: Australia.

NOTES Andropogoneae. Fl NSW 1993.

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