An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press

SOUTHWESTERN CUPGRASS

Illustration

GRASS FAMILY--Gramineae

SOUTHWESTERN CUPGRASS-Eriochloa gracilis (Fourn.) Hitchc.

DESCRIPTION-A spreading annual, 1 to 3 feet high, which reproduces by seed and by the prostrate stems rooting at the nodes. Without the flowering tops, southwestern cupgrass is very similar to the crabgrasses. It may be distinguished from large crabgrass, however, by the fact that the bright green leaves are not hairy. The flowering part is hairy, 2 to 6 inches long, with short, erect to spreading branches I to 2 inches long. The spikelets are about 3/16 inch long, tapering into a point at the tip. Each spikelet has a cuplike, sometimes darkened ring around the base, which distinguishes the cupgrasses from most other grasses. The yellowish oval grain is flat on one side and rounded on the other, about 1/3 inch long with a short sharp point at the tip.

DISTRIBUTION-Southwestern cupgrass is a native, and one of the most common and troublesome weeds in summer lawns. It is very commonly mistaken for crabgrass. It is also abundant along roadsides, city streets, cultivated fields, streams, washes, canyons, ditches, and pools throughout southern Arizona; 125 to 5,500 feet elevation; flowering June to October.

CANYON CUPGRASS-Eriochloa lemmoni Vasey & Scribn.

DESCRIPTION-An annual 2/3 to 2 or 3 feet high, similar to southwestern cupgrass, but the leaf blades are hairy. Frequently found on disturbed soil of roadsides, canyons, and washes in Cochise, Pima, and Santa Cruz counties; 2,400 to 5,700 feet elevation; flowering August to October.

Copyright (c) 1972 The Arizona Board of Regents



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