Eleocharis acutangula (Roxb.) Schult.

Global description

Eleocharis acutangula is a vivacious plant in marsh and water edge that grows in dense clumps from short rhizomes. The green stems, of triangular section, are septate transversely. They do not exceed 70 cm high and 4 mm in diameter. The leaves are reduced to sheaths, without blade. The inflorescence is terminal. It is an elongated cylindrical spikelet, located at the end of the stem, the same diameter as it, straw-colored, 2 to 6 cm long.

General habit

Vivacious stoloniferous plant, in clumps 30 to 70 cm high, composed of simple stems, without apparent leaf. Most are fertile and end with an inflorescence at the top of the stem.

Underground system

It is a short rhizome with fasciculate roots that emits long branched stolons that can reach 4 mm in diameter and are often terminated by a small tuber.

Stem

The stems are green. They are gathered in clumps. They are erect, measuring from 20 to 70 cm high, transversely septate, triangular section with very sharp angles, with smooth faces 2.5 to 4 mm wide.

Leaf

The leaves are reduced to a membranous sheath, tubular, rather loose, pointed at the end. The sheath is often of a color that goes from reddish to purplish.

Inflorescence

Single terminal spikelet, cylindrical, with pointed end, without bract at the base, 2 to 6 cm long, 3 to 6 mm in diameter, slightly wider than the stem. It is composed of many flowers.

Flower

The glumes are loosely imbricated in a helix. They are leathery, broadly oval to oblong-oval, 4.3 to 4.5 mm long, dirty yellow-straw colored. They present a prominent medial part traversed by numerous longitudinal veins and framed by two broad membranous margins. The flowers are bisexual. The perianth is formed of 6 to 7 filiform pieces usually barbed, brown russet, rather erect, a very short, the others as long as the ovary or exceeding it. The stamens are 2 to 3. The style is formed of an enlarged base, almost as wide as the ovary, surmounted by a stigma with 3 branches.

Fruit

It is an obovate achene flattened 1.5 to 2 mm long, unequally biconvex section, yellowish brown in color. It has about fifteen longitudinal ribs marked by a network of transverse cells. It is surmounted at the apex by the conical and enlarged base of the style.

Worldwide distribution

Eleocharis acutangula is widely distributed in all tropical regions of America, Africa and Asia as well as in North-East Australia.

https://www.gbif.org/species/2716800