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.

Eragrostis petraea

HABIT Perennial. Cataphylls evident. Butt sheaths glossy; glabrous. Culms 70–150 cm long; 4 -noded. Culm-internodes eglandular. Leaf-sheaths tight; eglandular; smooth; glabrous on surface; outer margin glabrous. Leaf-sheath oral hairs lacking. Ligule a fringe of hairs; 0.2–0.3 mm long. Leaf-blades flat, or involute, or convolute; 15–30 cm long; 2–4.4 mm wide; stiff. Leaf-blade surface ribbed; scabrous; rough adaxially; glabrous. Leaf-blade margins cartilaginous; eglandular; scabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle. Peduncle eglandular.

Panicle open; ovate; effuse; 20–46 cm long; 8–16 cm wide. Primary panicle branches 8–16 cm long. Panicle axis eglandular; scabrous. Panicle branches capillary; eglandular.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 3–10 mm long; eglandular.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 38–55 fertile florets; with diminished florets at the apex. Spikelets linear; laterally compressed; 16–27 mm long; 2.7–3 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes elongated between glumes; thickened; straight; 0.4–0.5 mm long.

GLUMES Glumes deciduous, or lower persistent, upper deciduous; similar; shorter than spikelet. Lower glume linear, or oblong; 0.3–0.6 mm long; 0.5 length of upper glume; membranous; without keels; 0–1 -veined. Lower glume lateral veins absent. Lower glume apex obtuse. Upper glume lanceolate; 0.6–1.2 mm long; 0.4–0.5 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Basal sterile florets barren; separately deciduous. Lemma of lower sterile floret similar to upper glume; lanceolate; 1 -veined. Fertile lemma lanceolate; 1.5–2 mm long; membranous; keeled; 3 -veined. Lemma lateral veins close to margins. Lemma surface smooth, or granulose. Lemma apex acute. Palea oblanceolate; with flaps narrower than body; hyaline; 2 -veined. Palea keels scaberulous; adorned above. Palea apex obtuse; scaberulous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; 0.3 mm long.

FRUIT Caryopsis with adherent pericarp; oblong; 0.5–0.6 mm long; reticulate.

DISTRIBUTION Australasia: Australia.

NOTES Eragrostideae. Lazarides 1997.

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