Aristida kerstingii Pilg.

Global description

Aristida kerstingii is a small plant with long alternate leaves linear and convoluted. The sheath is smooth. The ligule is very short and membrano-ciliated. The limb is slightly scabrid on the upper side. The inflorescence is a narrow panicle with uniflorous spikelets 25 to 40 mm long. They have smooth, long-arisen linear glumes. The lemma is shorter than the glumes and has an articulated top surmounted by a long trifid awn, finely scabrous whose column is twisted.

First leaves

The first leaves have a rolled aestivation They are carried by short sheath of 1 to 2 cm. The blade is very narrow, convoluted and 5 to 10 cm long. The ligule is very short and membrano-ciliated. The summit of the limb is long tapered.

General habit

The plant is erect. This species has low tillering. The individuals are most often solitary and slender or in small tufts. The plant is 30 to 90 cm tall.

Underground system

The roots are fasciculate.

Culm

The culm is cylindrical, glabrous and filiform. It is not knotted to nodes.

Leaf

The leaves are alternate, of light green color. The sheath is glabrous and not keeled. The ligule is very small, membrano-ciliated and 0.2 mm high. The blade is narrow, 2 to 4 mm wide and convoluted. It is filiform linear, 15 to 30 cm long and terminated by a long tapered apex. The margin and the upper surface are finely scabrous, while the underside is glabrous.

Inflorescence

The inflorescence is a narrow panicle along the axis and protruded by long trifid awns. It is 4 to 5 cm wide and 15 to 25 cm long. The spikelets are borne by short pedicels and usually clustered in bundles of 2 or 3.

Spikelet

Spikelets are all alike. They have a single, bisexual flower. They are flattened and measure 25 to 40 mm long and 0.4 mm wide. The glumes are linear filiform, at the top long aristate. The lower glume is 20 to 25 mm long, while the upper glume is 25 to 40 mm long with a 13 mm ridge. Both glumes are glabrous. The lemma is much shorter than the glumes. It is 6 to 8 mm long, the base is smooth and the upper part is finely scabrous. The summit is articulated and surmounted by a long trifid awn whose column is 3 to 7 cm long, strongly twisted and finely scabrous. The three branches measure 5 to 10 cm and are slightly scabrous. 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 rachole of 0.2 mm, pubescent.

Grain

The grain is linear. During the spread, it remains locked in the palea and the lemma become hard at maturity.

https://www.gbif.org/species/4126387