Lamarckia aurea (L.) Moench

Seedling

Juvenile leaf with broad sheath, blade at first flattened and keeled, 35-55 x 1-4.5 mm, hooked at apex, with visible midrib. Ligule fairly large, 5-10 mm, membranous and truncate. Plantlet with folded prefoliation, tender green and entirely glabrous.

Adult plant

Lamarckia aurea is an annual grass with an erect or spreading habit, forming small clumps, which can reach 30 cm high. Culms numerous abundantly leafy, glabrous, rough from bottom to top. Glabrous leaves, with disticous arrangement (in a plane), flattened sheath, of elliptic and keeled section, becoming yellowish papery when getting old. Blade flat 5-20 cm long and 3-7 mm wide, with scabrous margin, tender green. Ligule long, membranous entire or torn 5-8 mm. Inflorescence a one-sided contracted panicle, generally oval, up to 10 cm long, loose or dense, but always bristly and light golden yellow. Spikelets pedicellate, articulated on the axis, quickly deciduous and grouped by 4 or 5 in fascicles, the central fertile one of 3-5 mm, the others sterile of 4-8 mm, with around an involucre of imperfect sterile spikelets. The joints and axis long hairy. All spikelets with lower and upper glumes almost equal, membranous, with carina rough to the touch, mucronate at the top or very acute. Flowers of 3 types, those of the central sterile spikelets with a dozen mucronate lemmas, obtuse at the top, glabrous and in 2 rows, laterally compressed 4-8 mm long. Those of imperfect peripheral sterile spikelets with uninervate lemmas, bifid at the apex, glabrous and bearing a long ridge in the sinus. Those of fertile spikelets with elliptic lemma 2.5 mm, not keeled, 5-veined, scabrous, with bifid toothed apex and provided with a 6 mm long ridge; with barely bidentate palea, puberulent at the apex, as long as the lemma. The fertile floret is surmounted by sterile, aristate lemmas. The fruit is a 1-2 mm long, oblong caryopsis, disseminated with the entire fertile spikelet.

Origin

Lamarckia aurea is native to the Mediterranean-Iranian-Turanian region, as far as India.

Worldwide distribution

This species has been introduced in the west of the USA, in the west and south of South America, in South Africa and in Australia.

Algeria : Common species in all the Tell.