Aristida hordeacea Kunth

Global description

Aristida hordeacea is a small plant with long alternate leaves, linear and flat. Sheath is finely pubescent. The ligule is membrano-ciliated. The limb is finely scabrous on both sides. The inflorescence is a spike-like panicle with uniflorous spikelets, 7-10 mm long. They have scabrous linear glumes, terminated by a ridge and a lemma shorter than glumes and scabrous. The top of the lemma is articulated and surmounted by 3 long scabrous awns.

First leaves

The first leaves have a rolled prefoliation. They are carried by a sheath narrowing gradually to the ligule. The limb is flat, with no prominent mid-rib, sometimes convoluted, and finely scabrous on both sides. The ligule is short and membrano-ciliated. The top of the limb is wide or rounded.

General habit

The plant is erected. This species has low tillering. The individuals are most often in small tufts. The plant is 10 to 90 cm tall.

Underground system

The roots are fasciculate.

Culm

The culm is cylindrical and finely pubescent. The nodes are often tinged with purple.

Leaf

The leaves are alternate, light green in color and sometimes tinged with purple at the base of the sheaths. The sheath is glabrous or very slightly scabrid with a smooth margin and has a weak hull. The ligule is membrano-ciliated and 0.5 mm high. The limb is 3 to 8 mm wide and generally flat, sometimes convoluted. It is linear and 5 to 30 cm long and ends with a wide or rounded corner top. The margin and both sides are scabrous. The central rib forms a hull little marked.

Inflorescence

The inflorescence is a dense panicle, with dense spikelets spurting along the axis. It is oblong in shape, 2 to 3 cm wide and 5 to 15 cm long. It is light green to purplish.

Spikelet

Spikelets are all alike. They have a single, bisexual flower. They are flattened and measure 7 to 9 mm long and 0.5 mm wide. The glumes are lanceolate linear, 5 to 9 mm long, at the tip tapered to an edge 1 to 3 mm long. The lower glume is slightly shorter than the upper glume. They are hairless to slightly pubescent. The lemma is 5 to 7 mm long. It is traversed in the upper two-thirds by numerous scabrous longitudinal lines. The top of the lemma is articulated and surmounted by three scabrous awns, 2 to 5 cm long. Palea is shorter than lemma and membranous. The flower has 2 stigmas and 3 stamens.
At maturity, the spikelet disarticulates above the glumes revealing, at the base of the lemma, a short racheole of 0.5 mm, long pubescent.

Grain

The grain is linear, 4 mm long. During the spread, it remains locked in the palea and the lemma becomes hard at maturity.

https://www.gbif.org/species/4126800