Wright's Threeawn

Aristida purpurea var. wrightii

Poaceae


Description

Wright’s Threeawn is an erect, densely tufted bunchgrass that grows to 20 inches or 50 cm in height and does not branch at the nodes. It has more basal leaves than Oldfield Threeawn. Its leaves are thread-like and twisting.   The leaf collar is hairy which distinguishes it from other Aristida species  The seed head is a narrow panicle reaching 12 inches or 30 cm. It is purplish at first, turning yellow to gray when dry. Lower nodes have 2 to 10 spikelets. Each spikelet has three dark, stout, spreading awns up to 1 inch or 2.5 cm (about half the length of A. purpurea’s awns), with two bending horizontally about the midpoint. Its seeds are barbed. Glumes are unequal in length.  Wright’s Threeawn is a short-lived perennial, warm-season, native. It flowers whenever moisture is sufficient. It is one of the very first spring grasses becoming dormant in the summer and greening up again in the fall.  Fair grazing for livestock. Cattle prefer it more than sheep and goats though the USDA states that it may be injurious to livestock. Poor grazing for wildlife. 

Habitat

It is found on upland hills and plains. It grows best on calcareous to neutral sandy loams though it will also grow on clay loams. 

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