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.

Aegopogon tarahumara

HABIT Perennial; caespitose. Culms erect; 18–35 cm long; 3 -noded. Culm-internodes distally glabrous. Leaf-sheaths 0.8–8 cm long; mostly shorter than adjacent culm internode; pubescent. Ligule a ciliolate membrane; 1–1.8 mm long; pubescent on abaxial surface; entire, or erose; acute. Leaf-blades flexuous; filiform; flat, or involute; (2–)3.5–13 cm long; 0.2–1.3 mm wide. Leaf-blade surface pubescent; hairy on both sides. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 5–13; borne along a central axis; spreading; cuneate; unilateral; 0.5–1.4 cm long; bearing few fertile spikelets; bearing 2 fertile spikelets on each. Central inflorescence axis 3–6 cm long. Rhachis obsolete; deciduous from axis. Raceme-bases cuneate; shed with the raceme; acute.

Spikelets in pairs. Fertile spikelets pedicelled; 2 in the cluster. Pedicels oblong.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 4.5–7.5 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes similar; shorter than spikelet. Lower glume lanceolate; 3–5.8 mm long; 1 length of upper glume; membranous, or chartaceous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume surface pubescent. Lower glume apex acuminate; awned; 1 -awned. Lower glume awn 1.4–3.2 mm long. Upper glume lanceolate; 3–5.8 mm long; 0.8 length of adjacent fertile lemma; membranous, or chartaceous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume surface pubescent. Upper glume apex acuminate; awned; 1 -awned. Upper glume awn 1.4–3.2 mm long.

FLORETS Fertile lemma elliptic; laterally compressed; 3.6–7.3 mm long; membranous, or chartaceous; keeled; 3 -veined. Lemma surface pubescent. Lemma apex lobed; 3 -fid; with outer lobes longer; with lanceolate lobes; acute, or acuminate; awned; 3 -awned. Principal lemma awn 2–3.7 mm long overall. Lateral lemma awns arising on inner edge of lobes; 0.6–1.3 mm long; shorter than principal. Palea 3–4.6 mm long; 2 -veined. Palea surface pubescent; hairy on back; hairy above. Palea apex with excurrent keel veins.

FLOWER Lodicules 2; cuneate; membranous. Anthers 3; 2.2–2.8 mm long; orange. Ovary glabrous.

FRUIT Disseminule comprising a branch.

DISTRIBUTION North America: Mexico.

NOTES Cynodonteae. Peterson & Columbus 2011.

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