GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Andropogon insolitus

HABIT Perennial; caespitose. Culms erect; 25–50 cm long. Culm-internodes distally glabrous. Leaves mostly basal. Leaf-sheaths keeled; glabrous on surface. Ligule a ciliolate membrane; 1 mm long. Leaf-blades 10–25 cm long; 1–2.5 mm wide. Leaf-blade midrib conspicuous. Leaf-blade surface glabrous; hairless except near base. Leaf-blade margins scabrous; tuberculate-ciliate; hairy at base.

INFLORESCENCE Synflorescence compound; dense. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole lanceolate; 2–4 cm long. Peduncle pubescent above.

Racemes 2–5; paired, or digitate; 2–3 cm long. Rhachis fragile at the nodes; pubescent on surface; ciliate on margins. Rhachis internodes filiform. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 1.7–2.2 mm long; ciliate; with 1–1.5 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; 3–4.7 mm long; shorter than fertile; separately deciduous. 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; 4–4.8 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 laterally. Lower glume intercarinal veins absent. Lower glume surface flat. Upper glume lanceolate; membranous; 1-keeled; 3 -veined. Upper glume lateral veins obscure. Upper glume muticous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline. Fertile lemma lanceolate; 2 mm long; hyaline; without keel; 0 -veined. Lemma apex entire; muticous. Palea absent or minute.

FLOWER Lodicules 2. Anthers 3; 0.9–1.1 mm long.

DISTRIBUTION South America: northern South America.

NOTES Andropogoneae. Sohns 2001.

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