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Red
Threeawn
Common
Name(s):
Red Threeawn
Fendler Threeawn
Purple Threeawn
No-eatum
Scientific
Name:
Aristida
purpurea Nutt.
Scientific
Name Synonyms:
Aristida longiseta Steud.
Symbol:
ARPUL
Description:
Life
Span: Perennial
Origin:Native
Season: Cool
Growth Characteristics:
A
tufted bunchgrass, without rhizomes, growing 8 to 16 inches tall,
with fine stems. Starts growth in late spring and produces abundant
seeds. Red Threeawn reproduces from both seeds and tillers.
Seedhead:Narrow
to moderately spreading panicle, often over 6 inches long; spikelets
few, on pedicels, contains 1 floret, purplish-red at maturity; lemma
awn three-branched, 2 to 4 inches long and spreading at maturity;
seed enclosed by the awned lemma.
Leaves: Glabrous
except at collar; leaf blades narrow, rolled, rather stiff, up to
6 inches long, about as long as culm; leaves rolled in the bud;
hairy at collar; ligule a fringe of short hairs; auricles absent.
Ecological
Adaptations:
Red
threeawn is a strongly competitive native grass. If it dominates
a site, it is often and indicator of disturbed sites (i.e. roadsides),
or long-term, heavy, season-long use. It is common to upland and
semi-desert sites and has an ecological advantage in the shallower
soils on these sites. It is more common in the southern and lower
elevations of the state of Utah, being found at elevations between
2,500 feet and 9,000 feet, and in the 8 to 14 inches annual precipitation
zone.
Soils: It is most adapted to sand or
sandy loam soils, but does well on stony, gravelly soils.
Associated Species:
Big
sagebrush, cheatgrass, needle-and-thread,
western wheatgrass, blue
grama, and annual forbs.
Uses and
Management:
The
phenology of this plant explains its grazing response. It is poor
forage for both livestock and wildlife. It is worthless for forage
in the winter, although it may be used during drought years. By
starting its growth late in the growing season, it allows it to
escape from grazing. It has excellent drought resistance, giving
it an advantage over the other plants that are grazed during both
the early and late season. The awns may decrease fleece value, and
may also cause irritation and abscesses in the mouths and nostrils
and damage the eyes of grazing animals.
The excessive presence of red threeawn is an indicator of the need
for range improvement.
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