Fimbristylis ferruginea (L.) Vahl

Global description

Fimbristylis ferruginea is a medium-sized vivacious sedge, 45-75 cm tall, which develops in dense clumps from a short rhizome. The trigonal stems bear at their base leaves reduced to sheaths without silky hairs, then leaves with narrow and canaliculate limb. All leaves may be absent, reduced to their sheath. The inflorescence is simple or compound, a rather compact umbel subtended by 1 to 4 leaf bracts. The spikelets are ovoid-shaped, 10 mm in average and brown in color. The glumes are pubescent on the back in their upper part. The fruit is a largely obovoid biconvex achene of brownish color whose style is not persistent.

General habit

Vivacious plant, 45 to 75 cm tall, with filiform leaves and erect stems united in dense tuft. Plant usually hairless, sometimes slightly pubescent.

Underground system

Fasciculate roots from a short rhizome coated with greyish-brown scales.

Stem

The stems are erect and joined in a dense tuft. The stems measure from 15 to 75 cm in height with a diameter of 0.5 to 2 mm. The section is trigonal with obtuse angles. They are smooth and hairless.

Leaf

At the base, 2 to 4 leaves reduced to sheaths not bearing long silky hairs. The developed leaves are short, with an enlarged sheath. The blade is 1 to 15 cm long and 0.6 to 2.5 mm wide. They are narrow and rigid, canaliculate to more or less involute, striated, glabrous or pubescent, often viscous and scabrid on the margin. They present a short whitish ligule formed of a fringe of short hairs. The blade may be absent, all the leaves are then reduced to sheaths.

Inflorescence

The inflorescence is an umbel usually contracted, simple or rarely composed, which is 1.2 to 7 cm long. It is composed of 3 to 20 spikelets. It is subtended by 1 to 4 broadly basal leaf bracts, usually shorter than the inflorescence (1 to 3 cm long).

Spikelet

The spikelet is of conical ovoid shape or conical ellipsoid. It is 5.6 to 7.8 mm long and 3.2 to 3.4 mm in diameter. It is brown. The glumes are oval to obovate, with an obtuse mucronate apex. They are arranged spirally, of more or less equal size. They are 3 to 4.5 mm long, dull, ferruginous or blackish in color. Their edge is finely membranous, the back covered with a single rib. They have gray pubescence on the back, in the upper third. The flower consists of 3 stamens and a flattened style ciliated with 2 stigmas.

Fruit

The fruit is a largely obovoid achene, unequally biconvex, 1 to 1.2 mm long. Its surface is smooth. The style is not persistent at maturity. It is of a light orange to yellow-brown color.

Worldwide distribution

Fimbristylis ferruginea is widespread in the tropical, subtropical and Mediterranean regions of Africa up to the southern periphery of the Mediterranean, Asia and Oceania. In America it is only present in Central America, the Caribbean and Guyanas.

https://www.gbif.org/species/2708137