Pennisetum pedicellatum Trin.

Global description

Pennisetum pedicellatum is a grass with lanceolate linear leaves. The ligule is membrano-ciliated. The inflorescence is a panicle contracted into a woolly-looking, terminal false spike composed of involucres of bristles containing several spikelets, at least one of which is pedicelled. The bristles of the involucres are woolly at the base. The spikelets contain two flowers, the lower flower is male or sterile. The upper glume and the lower lemma are trifid at the top. The lemma and palea of ​​the fertile superior flower are smooth and shiny, enveloping the grain.

First leaves

The first leaves have a rolled prefoliation. The blade is lanceolate, 2 to 5 cm long and 9 to 12 mm wide. It is spread out. The ligule is membrano-ciliated. The sheath is dotted with 2 mm long hairs, especially near the ligule. The central rib forms a little marked gutter. The young leaves are often tinged with purple at the base.

General habit

Pennisetum pedicellatum is thick tuft. The plant generally has a strong tillering. It measures up to 150 cm in height.

Underground system

The roots are fasciculate.

Culm

The culm is cylindrical and glabrous. It is small to medium robust, 1 to 3 mm wide, greenish in color, often tinged with purple at the base. The knots are glabrous and light in color.

Leaf

The leaves are simple and alternate. The sheath is glabrous to weakly pubescent, especially in the upper part. It is cylindrical and has a round hull little marked. It is often tinged with purple. The ligule is membrano-ciliated, 1 mm high. The lamina is linear to lanceolate, with a pointed apex. It is erect obliquely and flat. The central rib forms a little marked gutter, triangular section. The blade is 10 to 45 cm long and 8 to 20 mm wide. The margin and the upper face are scabrous. The upper side of the limb presents at the base, some long scattered hairs.

Inflorescence

The inflorescence is a very contracted cylindrical panicle, having the appearance of a terminal spike, 5 to 15 cm long and 1 to 2 cm wide. The rachis is angular, with prominent ribs under the involucres of bristles. Each involucre is formed of more than 10 bristles 0.5 to 10 mm long, some up to 3 cm. The terminal part of the bristles is scabrous, the middle part is feathery and the basal part is woolly with tangled hairs giving the inflorescence a pink color more or less sustained. Inside the involucres are 1 to 5 spikelets, at least one of which is carried by a pedicel 0.5 to 3 mm long.

Spikelet

The spikelets are ellipsoid spindle-shaped, 3.5 to 6 mm long. They are composed of 2 flowers; the inferior is male or sterile, the superior is fertile. The lower glume is lanceolate and measures half the length of the spikelet. The upper glume and the lower lemma are as long as the spikelet. They are trifid at the top. The glumes and the lower lemma are membranous, dotted with fine woolly hairs. The lemma of the upper flower is hard, smooth and shiny. It is 2 to 4 mm long and has 3 dorsal veins. Its edges are partially closed on the palea, of the same nature. At maturity, the entire involucre is detached from the rachis.

Grain

The seed is fusiform, 1.5-2.5 mm long and remains included in palea and lemma.

 

Origin

Pennisetum pedicellatum is native to tropical Africa, from Mauritania and Senegal to Ethiopia and Kenya. It also occurs naturally in India.

Worldwide distribution

This species has been introduced into South America in Brazil, the Philippines and Australia.

https://www.gbif.org/fr/species/2706161