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 glaucescens

HABIT Perennial. Culms decumbent; 100–150 cm long; 5 mm diam.; wiry. Culm-internodes glaucous. Lateral branches lacking, or sparse. Leaf-sheaths loose. Ligule an eciliate membrane; 2–3 mm long; truncate. Leaf-blades linear, or lanceolate; 15–20 cm long; 10 mm wide. Leaf-blade surface glabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2; paired; appressed back to back; 12–15 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes oblong; 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; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels oblong; 2.5 mm long; ciliate; hairy on one margin.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; laterally compressed; 8 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; winged on keels; smooth; ciliolate on margins; acute, or acuminate; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pubescent; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; much thinner above; glaucous; 2-keeled; keeled all along; keeled laterally; wingless. Lower glume surface convex; asperulous and rugose; glabrous. Lower glume apex acuminate. Upper glume lanceolate; 1 length of spikelet; coriaceous; 1-keeled. Upper glume apex acuminate; muticous.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 7 mm long; hyaline; 3 -veined; acuminate. Fertile lemma lanceolate; 6 mm long; hyaline; without keel; 3 -veined. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 12–13 mm long overall; with twisted column. Column of lemma awn glabrous.

FLOWER Anthers 3; 3 mm long.

DISTRIBUTION Asia-tropical: Malesia.

NOTES Andropogoneae. Merrill 1997.

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