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.

Andropogon bourgaei

HABIT Perennial. Culms 100–150 cm long. Lateral branches sparse. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane. Leaf-blades 10–30 cm long; 4–6 mm wide. Leaf-blade surface scabrous; glabrous, or pubescent. Leaf-blade margins scabrous. Leaf-blade apex acute.

INFLORESCENCE Synflorescence compound; scanty. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole. Spatheole linear; 5–6 cm long. Peduncle antrorsely scabrous above.

Racemes 2–3; paired, or digitate; 4–6 cm long. Rhachis fragile at the nodes; plumose on margins. Rhachis hairs 1–2 mm long. Rhachis internodes filiform; 4–5 mm long. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets ascending; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 4–5 mm long; plumose.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; 5–5.5 mm long; longer than fertile. Companion sterile spikelet glumes chartaceous; 5 -veined; glabrous; acute; muticous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4–5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; membranous; 2-keeled; keeled dorsally. Lower glume primary vein scabrous. Lower glume intercarinal veins absent. Lower glume surface concave. Upper glume lanceolate; membranous; 1-keeled. Upper glume muticous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline; 2 -veined. Fertile lemma lanceolate; hyaline; without keel; 1 -veined. Lemma apex entire; muticous.

DISTRIBUTION North America: Mexico. South America: Mesoamericana.

NOTES Andropogoneae. N Amer Fl 1994.

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