Cyperus sphacelatus Rottb.

Global description

Cyperus sphacelatus is an annual plant with fasciculate roots, without rhizomes or tubercles, which develops in clumps 15 to 60 cm high. The stems are of triangular section. They are often of a characteristic yellow color at the base. The leaves are linear, grouped towards the base, shorter than the floriferous axis. The inflorescence is a simple to compound umbel subtended by long leaf bracts. It has light green linear spikelets 1 to 3 cm long with a purple median line. The grain is trigonal.

General habit

Annual, glabrous tufted plant, up to 60 cm tall.

Underground system

Fasciculate roots, no rhizome.

Stem

The stem is erect, small, 10 to 60 cm long and 1 to 2 mm in diameter. It is of triangular section, smooth and glabrous, a little thickened at the base. The stems form a compact tuft.

Leaf

The leaves are few by rod, inserted towards the base. The limb does not exceed 2/3 of the height of the stem. They have a sheath of color often of a characteristic golden green, whose length varies from 1 to 8 cm. The blade, rather rigid, is linear, pointed at the end, slightly bent. It is 5 to 17 cm long and 2 to 4 mm wide. Its margin is slightly scabrous. The faces are glabrous.

Inflorescence

The loose inflorescence is an open, simple or compound umbel of 1 to 8 rays (maximum length 8 cm) subtended by 3 to 6 spread leaf bracts, the longest of which reach 10 to 20 cm long. The rays carry the spikelets grouped by 5 to 12 in loose spikes, largely oval.

Spikelet

The spikelets are lanceolate linear, compressed, consist of 10 to 14 flowers. They are 6 to 35 mm long and 1.2 to 2 mm wide. They are light green in color and have a characteristic purple line. The glumes are oval, obtuse at the end, mucronate. They are light green, very often with a characteristic purple spot towards the base. They are 2 to 2.8 mm long. The rachillet of the spikelet is closely winged. The flower consists of 3 stamens and an ovary surmounted by a stigma with 3 branches.

Fruit

Ovoid to obovoid achene, of trigonal section, with concave faces finely punctuated. It is 1 to 1.5 mm long and 0.8 to 1 mm in section. Its color at maturity varies from brown to greyish-black.

https://www.gbif.org/species/2715182