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.

Schizachyrium semitectum

HABIT Annual. Culms erect; 20–55 cm long. Lateral branches ample. Leaf-sheaths keeled; glabrous on surface. Ligule a ciliolate membrane; 0.5 mm long. Leaf-blades flat, or conduplicate; 4–9 cm long; 1.5–3 mm wide. Leaf-blade surface pilose; with tubercle-based hairs. Leaf-blade margins scabrous.

INFLORESCENCE Synflorescence compound; scanty. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole linear; 2.5–3.5 cm long.

Racemes 1; single; 3–4 cm long. Rhachis fragile at the nodes; semiterete; villous on margins (below). Rhachis internodes cuneate; 4 mm long. Rhachis internode tip crateriform; with scarious rim.

Spikelets squeezed between internode and pedicel; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; 4 mm long; villous; hairy below.

STERILE SPIKELETS Companion sterile spikelets rudimentary; comprising 2 subequal glumes without lemmas; linear; dorsally compressed; 2 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; awned; one glume awned; with 3–5 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear, or lanceolate; laterally compressed; 6 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume linear, or lanceolate; 1 length of spikelet; coriaceous; 2-keeled; keeled all along; keeled frontally. Lower glume surface convex; pilose; hairy below. Lower glume hairs 2–2.5 mm long. Upper glume lanceolate; membranous; 1-keeled.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline. Fertile lemma oblong; 2.5 mm long; hyaline; without keel; 1 -veined. Lemma apex lobed; 2 -fid; incised 0.66 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 15 mm long overall; with twisted column. Column of lemma awn 6 mm long; glabrous. Palea absent or minute.

DISTRIBUTION North America: Mexico. South America: Mesoamericana.

NOTES Andropogoneae. Fl Nov Gal 1994.

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