An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press

SIXWEEKS GRAMA

Illustration

GRASS FAMILY-Gramineae

SIXWEEKS GRAMA-Bouteloua barbata Lag.

DESCRIPTION-An annual bunchgrass, branching from the base, from a shallow weak root, reproducing by seeds. The slender stems may be erect or prostrate, sometimes forming mats with the ends ascending, mostly less than 12 inches high, but may be much higher. The leaves are scarce, short, 3/8 to 1 1/2 inches long, and narrow, 1/16 inch or less broad.

There are 4 to 7 comblike flower spikes on each stem. These are persistent, and do not drop off easily. They are 3/8 to 3/4 inch long, with 25 to 40 spikelets arising from just one side of the spike stem; thus giving the spikes the characteristic comb-like appearance. Some of the flowering bracts are tipped by slender bristles, 1/8 to 1/12 inch long.

DISTRIBUTION-Sixweeks grama is a native grass of dry, disturbed, rocky, sandy, or caliche soil. It is a common weed throughout the state in waste places, roadsides, city streets, and in all kinds of summer or fall cultivated fields and orchards in the agricultural areas of southern Arizona. It also is abundant on mesas, hillsides, washes, and barren eroded places, on overgrazed or deteriorating ranges in the desert, desert grassland, or chaparral woodlands; 100 to 6,000 feet elevation, but mostly at the lower elevations; flowering principally from July to September or October, but throughout the year in good locations. This plant and sixweeks needle grama are alternate hosts for the beet leafhopper.

Copyright (c) 1972 The Arizona Board of Regents



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