Pycreus polystachyos (Rottb.) P.Beauv.

Global description

Pycreus polystachyos is a herbaceous vivavious sedge, tufted, with short and horizontal rhizomes. The stem is of triangular section, 25 to 80 cm high. The leaves are simple, alternate, linear length, the latter are as high as the inflorescence and 2 to 6 mm wide, flat. The inflorescence is terminal, 5 to 7 cm in diameter, composed of 5 to 8 flower stalks, emerging from the top of the stem and often very short, bearing many densely agglomerated erect spikelets, forming an ovoid mass of 0.75 to 1 , 5 cm wide. The spikelets are linear, flattened, with distichous glumes, straw color generally tinged with red. The seeds are biconvex.
 
First leaves
 
The first l leaves are linear, with short lamina, erect vertically, long tapered acute, having a large V-section, with the margin finely scabrous, the sheaths fitting in a tristichous way.
 
General habit
 
Herbaceous vivacious sedge, in dense tuft, with short and horizontal rhizomes.
 
Underground system
 
Roots are fibrous.
 
Stem
 
The stem corresponds to the flowering axis. It is trigonal, full, 2 mm in diameter and up to 25 to 80 cm high.
 
 
Leaf
 
The leaves are simple, alternate in a tristichous arrangement. The last leaves may be as high as or higher than the inflorescence. The sheath is trigonal and closed at the base. The lamina is linear, narrow, 2 to 6 mm wide, flat, with long tapered, acute apex. The faces are glabrous, the margin is scabrous.
 
Inflorescence
 
The inflorescence is a simple or compound umbel, 5 to 7 cm in diameter, sub-tended by 4 to 6 leafy bracts, narrowly linear, horizontal, very variable in size, up to 12 cm long. The umbel is composed of 5 to 8 flowering stalk, often very short, bearing many densely agglomerated spikelets, erect, forming an ovoid mass,0.75 to 1.5 cm wide.
 
Spikelet
 
The spikelets are linear, flat, 6 to 13 mm long and 1.5 mm wide, with distichous glumes, straw colour generally tinged with red. The first 2 glumes are empty. The glumes are oblong oval, shortly mucronate, 2 mm long, usually straw color tinged with red, rarely brownish red.
 
Fruit
 
The fruit is an oblong achene, biconvex, slightly asymmetrical, 1.5 mm long, topped by a bifid style, without thickening at the base of the style. The integument is finely dotted.
 

Worldwide distribution

Pycreus polystachyos occurs in Central and South America; Africa; Iberian Peninsula and Italy; Middle East; Indian subcontinent, SE Asian subcontinent, China, Japan, Korea, Philippines, Indonesia, Australia and Pacific Islands.

https://www.gbif.org/fr/species/2730392