Cyperus distans L.f.

Global description

Cyperus distans is an annual to vivacious erect plant, with short rhizomes, which forms tufts of 35 cm to 1 m high in general. The leaves are long and narrow, with scabrous margin. The trigonal stem carries a diffuse inflorescence, a large compound umbel subtended by leaf bracts that surpasses it. Terminals floral axis carry cylindrical and elongated linear spikelets of 10 to 30 mm long, spread out more or less at right angles, reddish-brown in color and with deciduous glumes.
 
First leaves

The first leaves are sheathing, with erect and pointed short lamina.
 
General habit

Plant, growing in erect tuft, 35 to 100 cm high.
 
Underground system

Think rhizomatous stump, reddish to black in colour, emitting stolons that can reach 4 cm long with a diameter of 1.5 mm.
 
Stem
 
The inflorescence axis is solitary or in small groups, slender to rather robust, thickened at the base, triquetrous and smooth surface. They measure 30 cm to 1 m high with a thickness of 2 to 3 mm on average, up to 5 mm. Their base is surrounded by a rather elongated sheath, light brown in colour.
 
Leaf

The leaves are approximately the same length as the stem. At the base is a closed sheath. The blade is narrow linear (4-10 mm wide), erect or falling, flat or in open acute V at the apex, intense green on the upper side, yellow on the underside. The margin is scabrous.
 
Inflorescence

The inflorescence is a large compound umbel, diffuse, 20 to 40 cm in diameter. It is underpinned by 4 to 6 leafy bracts, 20 to 60 cm long, similar to the leaves, of which 2 or 3 lower bracts exceed it. The primary floral axis, 6 to 12 in number, is very unequal. They are 8 to 20 cm long. The terminal umbels with many rays (15) are in the axils of short linear bract. Each floral axis carries 5 to 15 spikelets spaced apart from each other.
 
Spikelet

The cylindrical spikelets are linear and narrow, with flexuous rachis, distinctly winged. They are 10 to 30 mm long with a diameter of 0.8 to 1 mm. They are red to reddish brown and with deciduous glumes. They are composed of 8 to 35 flowers with 3 stamens and trifid style. Each flower is wrapped in an oblong-oval to elliptic, obtuse, membranous, reddish brown, glume, (1.8-2.5 mm long) with 3 to 5 veins, with greenish keel and upper hyaline, white margin.
 
Fruit

The fruit is a trigonal to pointed obtuse achene, oblong or narrowly obovate-oblong, black-brownish in color. It is finely punctuated. It measures 1.5 to 1.7 mm long and 0.3 to 0.5 mm wide.