Aristida purpurea is more commonly known as purple threeawn (other varieties include red threeawn, wiregrass, and democrat grass). This native grass is found throughout western North America and the Midwest, as well as a few states on the East Coast (image 3,4). It is distributed at elevations between 600 and 1,350 meters in the southwest.
Characteristics
Aristida purpurea gets its name from the purple flowers it produces in the summer and fall (image 1). It is a semi-deciduous perennial which needs very little water and can grow to 75cm high and 60cm wide. The fruits of this upright bunch grass are also purplish in color (image 5) and have three awns at the tips which can be anywhere from 2.5-13cm long (image 2). It is with the use of these awns that the seeds are dispersed (via animals).
Ecology/Uses
This grass has very little foraging value for animals. Bison occasionally graze on the grass but, because of the pointy awns, it is generally unpalatable to animals. However, it does have another ecological importance. Purple threeawn is one of the first grass species to become established following a disturbance. Because it is a seed-banking species, purple threeawn can regenerate rather quickly following a fire. Seeds are stored underground, keeping them insulated and unharmed by fires. Furthermore, because of its little need for water and drought tolerance, this grass is used regularly in landscaping and is a good candidate for xeriscaped areas.