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.

Microstegium borianum

HABIT Perennial. Culms robust; 128 cm long. Culm-internodes distally glabrous. Culm-nodes pubescent. Lateral branches lacking. Leaf-sheaths pubescent. Ligule an eciliate membrane; 2–4.5 mm long. Leaf-blades lanceolate; 10–25 cm long; 15–20 mm wide. Leaf-blade surface pilose; hairy on both sides; with tubercle-based hairs. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 3–4; digitate; 5–10 cm long. Rhachis fragile at the nodes. Rhachis internodes filiform.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; angular; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas; linear; 3 mm long.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or oblong; dorsally compressed; 5.5–6 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base obtuse; attached transversely.

GLUMES Glumes dissimilar; firmer than fertile lemma. Lower glume elliptic; 1 length of spikelet; coriaceous; 2-keeled; keeled obtusely; 9 -veined. Lower glume primary vein ciliate. Lower glume surface with a longitudinal median groove. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; membranous, or chartaceous; 1-keeled; 5 -veined. Upper glume primary vein scabrous. Upper glume awned; 1 -awned. Upper glume awn 1 mm long.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret lanceolate; 4.5 mm long; hyaline; 3 -veined; ciliate on margins; fringed in the middle; dentate; 2 -fid. Palea of lower sterile floret 3.5–4 mm long. Fertile lemma oblong, or ovate; 3.5–4 mm long; membranous; without keel. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 9–10 mm long overall; with a straight or slightly twisted column. Palea 1 length of lemma; hyaline. Palea apex dentate; 2 -fid.

FLOWER Anthers 3; 3 mm long.

DISTRIBUTION Asia-tropical: India.

NOTES Andropogoneae. Sur 2006.

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