Cyperus eragrostis Lam.
Nutsedge 

Family:  Cyperaceae

Habit:  Perennial with short, thick rhizomes, coarse fibrous roots, and triangular stems; 10 to 90 cm. tall.

Distribution:  Common in vernal pools, stream banks, and ditches of California, Oregon, and temperate South America.

Seed unit:  Achene.

Seed:  Achene three-sided, 1.2 to 1.4 mm., stalked, finely reticulate, black to brown; tip beaked.  Some achenes are still enclosed in straw-colored, ovate, three-nerved scales.  Achenes should be removed from pieces of plant material and the scale for the AOSA pure seed definition.

Embryo:  Basal.

Purity instructions:   Pure seed definition:
AOSA: PSU #28 – Intact achene, whether or not a seed is present, with or without beak.   Piece of broken achene larger than one-half of the original size, unless no seed is present.

Lab notes:  In some samples, low germination may be due to the presence of empty achenes.  When a sample is received that appears unmilled; immature, light colored, “obviously empty” achenes could be removed and categorized as inert matter.  It is recommended that this be communicated on the final data sheet as the removal of immature achenes will alter the final viability results.

Average pure seed units per gram:  8,705 seeds per gram (based on AOSA pure seed units only from 8 samples received for testing from 1994 to 2003).

Range of percent pure seed:  44% to 99%

Range of percent inert:  1% to 55%

Description of inert:  Plant material.

Planting instructions:  400 seeds, TB, 21 days @ 20-35°C; for fresh and dormant seed, prechill recommended.