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.

Eustachys petraea

HABIT Perennial; caespitose. Stolons present. Basal innovations flabellate. Culms erect; 25–80 cm long; 2–3 mm diam. Culm-nodes glabrous. Leaf-sheaths keeled. Ligule a ciliate membrane; 0.2 mm long. Leaf-blades flat, or conduplicate; 6–20 cm long; 4–5 mm wide. Leaf-blade midrib keeled beneath. Leaf-blade surface glabrous. Leaf-blade margins scabrous. Leaf-blade apex obtuse; apiculate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2–6; paired, or digitate; unilateral; 4–10 cm long; 2 mm wide. Rhachis angular. Spikelet packing broadside to rhachis; crowded; regular; 1 -rowed.

Spikelets pectinate; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets obovate; laterally compressed; 1.6–2 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pilose.

GLUMES Glumes persistent; dissimilar; shorter than spikelet; thinner than fertile lemma; gaping. Lower glume lanceolate; 0.9–1.3 mm long; 0.8–0.9 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume surface puberulous. Lower glume apex acute. Upper glume oblong; 1.1–1.5 mm long; 0.5–0.7 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume surface puberulous. Upper glume apex lobed; 2 -fid; obtuse; awned; 1 -awned. Upper glume awn 0.3–0.5 mm long.

FLORETS Fertile lemma oblate; laterally compressed; 1.6–2 mm long; coriaceous; dark brown; shiny; keeled; 3 -veined. Lemma midvein ciliate. Lemma surface glabrous. Lemma margins ciliate, or pubescent. Lemma apex acute; muticous, or mucronate. Palea 2 -veined. Apical sterile florets 1 in number; barren; cuneate; 1 mm long. Apical sterile lemmas scabrous; truncate.

FLOWER Anthers 3; 0.6 mm long.

DISTRIBUTION Pacific: southwestern, northwestern, and north-central. North America: south-central USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, western South America, Brazil, and southern South America.

NOTES Cynodonteae. SAR 2004.

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