by Karen J. Albins,
Native Plants Class 2003
Common names: groundcover milkvetch (1), Loco weed
Family: Fabaceae
Synonymy: Astragalus datilensis (Rydb.) Tidestrom (1)
Astragalus Batidophaca humistrata (A.Gray) Rydb, Pisophaca
datilensis Rydb, Tium huministratum (A.Gray) Rydb, Tragacantha
humistrata (A.Gray) Kuntze (2)
Etymology: The generic name Astragalus, meaning "ankle-bone"
in Greek refers to a plant with vertebra-like knotted roots. (4) The
specific epithet, humistratus refers to the prostrate growth form of
the plant.
Identification
Growth form: Gerbaceous, growing close to ground
Roots: Knotted and short
Stems: Decumbent spreading stems or completely prostrate, silver
color, 15-60 cm in length, (3)
Leaves: 9-19 leaflets per leaf, oblong to lanceolate, 3-7 mm
in length, with small short sharp hairs on both sides or glabrous on
top side while as above on bottom side.(3)
Inflorescence/flowers: 3-30 purple/white flowers in clusters
on short dense racemes, corolla 6-12 mm in length (3)
Fruit: Pods 6-20 mm in length, with short sharp hairs. (3)
Similar species: There are many species of Astragalus throughout
the United States, including six different variations of the species
Astragalus humistratus; humistratus, arehosackiae,
crispulus, humivagans, humivagans, and
tenerrimus. (1)
Ecology
Life history: Perennial
Native/introduced: Native (1)
Photosynthetic pathway:
Phenology: May through September
Distribution: Nevada, Arizona, Utah, and Texas (1) Colorado to
Nevada, to South New Mexico. (3)
Uses
References:
1. USDA, NRCS. 2002. The PLANTS Database, Version 3.5 (http://plants.usda.gov).
National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
2. www.ildis.org/LegumeWeb/6.00/taxa/10803.shtml
3. McDougall, W.B. Seed Plants of Northern Arizona, 1973 (253). Northern Arizona Society of Science and Art Inc. Flagstaff AZ
4. Gledhill, D. The Names of Plants, 3rd edition. Cambridge University Press, 2002
