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.

Ectrosia laxa

HABIT Annual; caespitose; clumped loosely. Culms erect, or geniculately ascending; slender; 30–60 cm long; 1–5 -noded. Culm-internodes distally glabrous. Lateral branches lacking. Leaf-sheaths loose; striately veined; pilose; with tubercle-based hairs. Leaf-sheath oral hairs bearded. Ligule a fringe of hairs. Leaf-blades 7–15 cm long; 1–2.6 mm wide. Leaf-blade surface scaberulous; rough adaxially; pilose; hairy on both sides. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle. Peduncle pilose above.

Panicle open; oblong; 7–15 cm long; 6 cm wide. Primary panicle branches ascending; 2–3.5 cm long. Panicle axis angular; scaberulous; pilose. Panicle branches flexuous; scabrous; pilose.

Spikelets spreading; solitary. Fertile spikelets pedicelled. Pedicels linear; 1–2 mm long; ciliate.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with diminished florets at the apex. Spikelets linear; laterally compressed; 8–11 mm long; 1.3–1.5 mm wide; breaking up at maturity; disarticulating above glumes but not between florets. Rhachilla internodes curved; 1–1.7 mm long; scaberulous.

GLUMES Glumes deciduous; similar; shorter than spikelet. Lower glume lanceolate; 2–3 mm long; 0.66–0.75 length of upper glume; membranous; 1-keeled; 1–3 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent, or obscure. Lower glume apex acuminate. Upper glume lanceolate; 3–4 mm long; 0.66 length of adjacent fertile lemma; membranous; 1-keeled; 1–3 -veined. Upper glume primary vein scaberulous. Upper glume lateral veins absent, or distinct. Upper glume apex cuspidate.

FLORETS Fertile florets increasing in size upwards; with the lowest dissimilar. Lowest fertile lemma 0.75–0.9 length of adjacent lemma; lobed (emarginate); mucronate. Fertile lemma lanceolate; dorsally straight along back; 3.2–10.7 mm long; coriaceous; keeled; 3 -veined. Lemma midvein scaberulous. Lemma surface smooth, or asperulous. Lemma apex acute, or acuminate; awned; 1 -awned. Principal lemma awn 2–4.7 mm long overall. Palea 2.8 mm long; 2 -veined. Palea keels scaberulous; ciliolate. Palea surface asperulous. Apical sterile florets 7–8 in number; barren; rudimentary. Apical sterile lemmas awned; 1 -awned. Apical sterile lemma awns 10–13 mm long.

FLOWER Anthers 3; 0.4 mm long.

FRUIT Caryopsis with adherent pericarp; lanceolate; 1.1–1.7 mm long.

DISTRIBUTION Australasia: Australia.

NOTES Eragrostideae. Blake.

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