Actinoscirpus

Scientific name

Actinoscirpus (Ohwi) R. W. Haines & Lye

Common names

giant bulrush, greater club-rush

Family

Cyperaceae

Similar genera

Cyperus, Juncus, Schoenoplectus

Native distribution

India to southeast Asia, China, Japan, Malaysia, northern Australia

Species cultivated

Actinoscirpus grossus (L.F.) Goetgh. & D.A. Simpson

Adventive distribution

information not available

Weed status

sometimes considered invasive

Habit

inundated to emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
sedge

Brief description

Perennial. Stolons long, often with a small tubertuber:
(n) un underground storage organ formed from swelling of a stem
at the apices; culms sharply triangular, sides concave, smooth or slightly roughened, septateseptate:
(adj) divided or partitioned by cross-walls
, spongy. Leaves basalbasal:
(adj) at or pertaining to the base, or point of attachment
; ligulateligulate:
(adj) possessing or with a ligule
; sheaths spongy, with prominent cross-veins, yellowish; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
linear, keeledkeeled:
(adj) having a keel; sharply creased
below, apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
acuteacute:
(adj) tapering to a sharp, pointed apex with more or less straight sides; broader than acuminate; forming an angle of less than 90 degrees
, base sheathing, marginmargin:
(n) edge; rim
scabrous, venationvenation:
(n) the arrangement of veins in a leaf
parallel. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
terminal, a compoundcompound:
(adj) with two or more like parts, as in a compound leaf; divided into two or more subsidiary parts or orders, as in a compound inflorescence
anthelaanthela:
(n) a type of cymose corymb inflorescence, in which the lateral flowers are higher than the central ones
(similar to a paniclepanicle:
(n) an indeterminate, branched (often much-branched) inflorescence; the ultimate units may be of a different inflorescence type
); involucral bracts 3-4, leaf-like, exceeding inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
; spikelets numerous.

Natural habitat

in inundated places and shallow waters, ditches, pools, marshes, swamps, paddy fields; often forming a large community

Additional comments

Actinoscirpus grossus is the sole species in this genus.