Cyperus eragrostis Lam.

Family: Cyperaceae

Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)

Cyperus vegetus Willd.

Pertinent Common Names (particularly those used in California; go to GRIN for other common names)

tall flatsedge, drain flatsedge

Primary Disseminule Type

fruit (with or without enclosing floral bract)

Description (diagnostics are in brown)

Spikelet oblong, strongly compressed, (5)10–20 mm long x (2.2)3–3.5 mm wide, consisting of up to 30(50) florets.

Floral bracts ovate, 2–2.3 mm long, apex acute, golden brown, basally 2-keeled, 3-veined, midvein minutely roughened at apex, deciduous with fruit.

Fruit an achene, stalked, obovate in outline, cross-section trigonous (each side concave), 1–1.5 mm long x (0.5)0.7–0.9 mm wide. Surface glabrous, shiny, with an iridescent, semi-transparent, honeycombed layer covering a dark brown to black puncticulate layer. Apex apiculate, often with a beak (i.e., stylar remnant) 0.2–0.3 mm long.

Similar Species

Cyperus esculentus

Risk Assessment (codes in yellow or red indicate cause for concern; assessments are current as of mid-2011; click AUQP, NZBORIC, or NZBPI for access to the most recent versions of these databases and possible assessment changes)