Lamarckia aurea

HABIT Annual. Culms geniculately ascending; 10–15(–40) cm long. Ligule an eciliate membrane; 5–8 mm long. Leaf-blades 5–20 cm long; 3–7 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; ovate; secund; 3–6 cm long; gathered into fascicles. Panicle axis bearing deciduous spikelet clusters. Panicle branches pilose.

Spikelets subtended by an involucre. Fertile spikelets pedicelled; 1 in the cluster. Companion sterile spikelets pedicelled; 3 in the cluster (and a rudiment). Involucre composed of imperfect spikelets; cuneate; base truncate. Pedicels filiform; pubescent.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas; linear; laterally compressed; 4–8 mm long; longer than fertile; deciduous with the fertile. Companion sterile spikelet glumes membranous; glabrous; entire; acuminate; mucronate, or awned; both glumes awned; with 0.5–1 mm long awn. Companion sterile spikelet lemmas 8–15; exserted from glumes; muticous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 3–5 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes similar; exceeding apex of florets; similar to fertile lemma in texture. Lower glume lanceolate; 3–5 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate; mucronate, or awned; 1 -awned. Lower glume awn 1 mm long. Upper glume lanceolate; 3–5 mm long; 1.6 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate; mucronate, or awned; 1 -awned. Upper glume awn 1 mm long.

FLORETS Fertile lemma elliptic; 2.5 mm long; without keel; 5 -veined. Lemma surface scabrous; rough above. Lemma apex dentate; 2 -fid; incised 0.2 of lemma length; awned. Principal lemma awn from a sinus; 6 mm long overall. Palea 1 length of lemma. Apical sterile florets 1 in number; barren; ovate; 0.5 mm long. Apical sterile lemmas awned; 1 -awned. Apical sterile lemma awns 6 mm long.

FLOWER Anthers 3; 0.5 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum elliptic.

DISTRIBUTION Europe: southwestern and southeastern. Africa: north, Macaronesia, northeast tropical, and south. Asia-temperate: western Asia and Arabia. Asia-tropical: India. Australasia: Australia. Pacific: north-central. North America: southwest USA, south-central USA, and Mexico. South America: Mesoamericana, western South America, and southern South America.

NOTES Poeae. Tothill.

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