An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press

DESERT SENNA, cove senna


PEA FAMILY-Leguminosae

DESERT SENNA-Cassia covesii Gray

DESCRIPTION-A bushy perennial covered with fine white hairs reproducing by seeds only. The stems are 1 to 2 feet high, branching from a woody base. The grayish green leaves are 1 to 2 inches long, including the stalks. They are divided into 2 to 4 pairs of large oblong, point tipped leaflets, 1/3 to 1 1/4 inches long.

The flowers are in several to many stalked clusters at the top of the stems, and in the leaf axils. They have 5 large yellow petals about 1/2 inch long, with reddish veins, and 10 stamens with large orange anthers. The slightly curved pods, 3/4 to 1 1/3 inches long, are tipped by a stiff point about 1/8 inch long. They pop open with force when mature, throwing the seeds some distance from the plant. The pinkish brown seeds are pearshaped, deeply wrinkled, and flattened, about l/8 inch long.

DISTRIBUTION-Desert senna is a very common native weed of dry disturbed soil throughout the state, along roadsides and waste places; also common on rocky slopes, mesas, sandy river bottoms, and washes in desert, northern desert, and desert grassland ranges; mostly from 1,000 to 3,500 feet elevation; flowering from spring until fall, March to October.

TWOLEAF DESERT SENNA-Cassia bauhinioides Gray

DESCRIPTION-Looks almost exactly like desert senna, except the leaves are divided into just 2 leaflets (1 pair), and there are only 2 flowers in each stalked axillary cluster, with no flowers borne at the tip of the stems.

DISTRIBUTION-It has the same distribution and habitat as desert senna, but at slightly higher altitudes, and is more common on northern Arizona desert rangelands; 2,000 to 5,500 feet elevation; flowering from April to September.

Copyright (c) 1972 The Arizona Board of Regents

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