An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press

MONOLEPIS, patota, patata



MONOLEPIS-Monolepis nuttalliana (Schult.) Greene

DESCRIPTION-Monolepis is a low succulent annual with a taproot, and repro- duces only by seed .The stems are erect, spreading, or sometimes prostrate on the ground, then ascending, 3 to 15 inches long, and usually not more than 8 inches high. The bright green alternate leaves, 1/3 to 2 1/2 inches long, are nearly hairless. They are lanceshaped, or have a pair of lobes toward the base. The inconspicuous greenish flowers are clustered in the axils of the leaves. The tiny, flat dark gray seeds are circular, with a thicker rim, about 1/25 inch in diameter, and a minutely pitted surface.

DISTRIBUTION-Monolepis grows in moist soil of alkaline depressions, alluvial flood plains, along roadsides and barren areas on mesas, throughout the state in the desert, northern desert, or rarely to yellow pine; 100 to 7,500 feet elevation (mostly below 3,000). It is prolific in southern Arizona in early spring, where it is ephemeral, sometimes covering large areas in almost pure stands. It flowers from January to April or May. Monolepis is a common but unimportant weed in cultivated crops, where it may flower and fruit from spring until late fall, as in the Yuma and Salt River Valleys. This plant is still used as greens by the Indians.

POISONOUS PROPERTIES-Livestock relish monolepis, and ordinarily it is good feed. After a wet season it contains large amounts of nitrates, which are not poisonous, but become dangerous when eaten in large amounts. A chemical reaction takes place, aided by microorganisms in a ruminant's stomach, which quickly changes the nitrates to poisonous nitrites. Poisoning occurs so quickly that there is little time for warning symptoms.

Copyright (c) 1972 The Arizona Board of Regents

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