Ischaemum afrum (J.F.Gmel.) Dandy

Global description

Ischaemum afrum is a vivacious grass in a thick tuft. The leaves are long and tapered, narrowed at the level of the ligule and glabrous. The ligule is long and membranous. The inflorescence comprises 2 to 3 linear, digitized racemes. The spikelets are grouped by 2, one sessile and concave, the other carried by a bulging pedicel. Glumes are membranous, lemmas and translucent paleas. The upper lemma of the sessile spikelet is surmounted by a geniculate and twisted awn. The lower flower is male, the upper is fertile. The grain is free and fusiform orange.

First leaves

The first leaves have a rolled prefoliation. The blade is lanceolate to linear, 1 to 5 cm long and 5 to 8 mm wide. The base is narrowed, the apex is sharp tapered. The margin is smooth. The blade is erect obliquely and glabrous. The main rib forms a gutter. The ligule is tall and membranous. The sheath is cylindrical and narrowed at the top. It is sometimes longer than the blade and quickly departs from the culm. It is totally hairless.

General habit

The plant is tufted bunch can become very dense and very thick over the years. The culms are erect and interconnected by short rhizomes. This species is 0.5 to 1.5 m tall.

Underground system

The roots are fasciculate.

Culm

The culm is cylindrical, 3 to 5 mm wide. It is hairless. The knots are dark in color.

Leaf

The leaves are alternate, erect obliquely or drooping, for the upper leaves, in the terminal part of the limb. They are spread throughout the stubble. The sheath is cylindrical and weakly keeled. She is totally hairless and narrowed at the top. It departs quickly from the stubble. The ligule is membranous and 2 mm high. The lamina is linear, with a narrowed base and a long pointed apex. It is 10 to 50 cm long and 4 to 10 mm wide. He is totally hairless. The main rib forms a little marked gutter.

Inflorescence

The inflorescence is composed of 2 to 3 linear, linear racemes. They are 10 to 20 cm long. The rachis is articulated and fragile. It is hairless or covered with a yellowish pubescence. The internodes are 4 to 5 mm long and swollen.

Spikelet

Spikelets are of two types. Sessile spikelets are concave on the back, 5-8 mm long and chartaceous. They include 2 flowers. The lower glume is bicarinated and concave. It is 5 mm long, membranous and has stiff bristles at the base. The upper glume is oval and compressed, at the top in acute corner. It is 7 mm long, membranous and has stiff hairs at the base. The 2 flowers are included in translucent lemmas and paleas. The lemma of the upper flower is surmounted by a geniculate awn, 5-10 mm long and twisted in the lower part. The lower flower is male, comprising 3 stamens. The upper flower is female. Pedicellate spikelets are borne by a bulging pedicel, 3 to 4 mm long and with stiff bristles at the base. They include 2 flowers, sometimes absent in the spikelets of the end of the raceme. The lemma of the upper flower is not aristate or very short.

Grain

The grain is free. It is fusiform, of triangular section and 3 mm long. The tegument is smooth, orange in color.

http://www.plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:406103-1