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.

Sorghastrum nudipes

HABIT Perennial; caespitose. Rhizomes elongated. Basal innovations extravaginal. Culms erect; 55–120 cm long; 1–2.5 mm diam. Leaf-sheaths 7–20 cm long; glabrous on surface. Ligule an eciliate membrane; 15–25 mm long. Leaf-blades 10–30 cm long; 2–5 mm wide. Leaf-blade surface smooth, or scabrous; glabrous, or pubescent. Leaf-blade margins scabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme. Peduncle 15–30 cm long.

Panicle open; oblong; 10–30 cm long. Panicle axis smooth. Panicle branches capillary.

Racemes bearing a triad of spikelets, or few fertile spikelets; 1–3 fertile spikelets on each. Rhachis fragile at the nodes. Rhachis internodes filiform.

Spikelets in pairs, or in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster, or 2 in the cluster. Pedicels filiform; 3–6 mm long; pubescent.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 5.5–7.5(–9) mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse.

GLUMES Glumes dissimilar; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; chartaceous, or coriaceous; without keels; 7–9 -veined. Lower glume lateral veins distinct. Lower glume surface pubescent. Lower glume apex truncate. Upper glume oblong; 1 length of spikelet; chartaceous, or coriaceous; without keels; 5 -veined. Upper glume surface glabrous, or pubescent; hairy below. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 5–6.5 mm long; hyaline; 2 -veined; ciliate on margins; dentate; 2 -fid. Fertile lemma oblong; 3.5–5.3 mm long; hyaline; without keel; 3 -veined. Lemma margins ciliolate. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; straight, or geniculate; 12–18 mm long overall; with twisted column. Column of lemma awn hispidulous. Palea absent or minute.

FLOWER Lodicules 2; glabrous. Anthers 3; 3–4 mm long.

FRUIT Caryopsis 2–3 mm long.

DISTRIBUTION Africa: west-central tropical, southern tropical, and south. North America: Mexico.

NOTES Andropogoneae. Davila 1993.

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