An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press

YELLOW NUTSEDGE, yellow nutgrass

Illustration

SEDGE FAMILY-Cyperaceae

YELLOW NUTSEDGE-Cyperus esculentus L.

The nutsedges are prohibited noxious weeds in Arizona.

DESCRIPTION-A tough erect perennial, 1 to 3 feet high, reproducing by seeds and by many deep, very slender rhizomes which form weak runners above the ground, and small tubers or nutlets at the tips of underground stems. The tubers are dark, unevenly globeshaped, 3/8 to 3/4 inch long, and edible, tasting somewhat like almonds. Near the base of the triangular stem, a cluster of 3-ranked, grasslike leaves arises which are often longer than the stem, and l/8 to 1/3 inch broad. The umbrellalike flowering tops have a few threadlike stems of different lengths radiating out like spokes from the stem tip. These have numerous yellowish to golden brown spikelets on the upper part. The spikelets are very narrow, flattened, 1/16 to 1/12 inch broad, and 1/4 to l (or l 1/2) inch long. The leaves beneath the flowering tops are 2 to 10 inches or more long, and some are much longer than the flowering stems. The brownish 3-angled achene, about 1/16 inch long, is widest at the top.

DISTRIBUTION-Yellow nutsedge, an Old World introduction, is a noxious weed of wet soil. The nutsedges are the most difficult weeds to control in cultivated fields, often forming a solid cover over large areas in cotton fields, sorghum and alfalfa pastures, flood plains, dams, ditches, and along streams and roadsides. Yellow nutsedge is common throughout most of the state; 100 to 8,200 feet elevation; flowering May to November or fall frosts.

PURPLE NUTSEDGE, purple nutgrass-Cyperus rotundus L.

DESCRIPTION-Purple nutsedge closely resembles yellow nutsedge, but the mature stems are usually longer than the basal leaves. The leaves below the flowering heads, 1 to 5 inches long, are about the same length as the flower stems, few are longer. The spikelets are dark brown-purple, and the runners are fewer, woody, and thicker. The nutlets are oblong and covered by persistent reddish scales, whereas they are almost smooth in yellow nutsedge at maturity, and unevenly globose.

DISTRIBUTION-Purple nutsedge is largely confined to the valleys of southern Arizona; 100 to 4,000 feet elevation; flowering from May to fall frosts. In all summer crops, in lawns, ditchbanks, and field borders; the rhizomes, runners, and tubers make the nutsedges almost impossible to eradicate.

Copyright (c) 1972 The Arizona Board of Regents



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