The two-grooved milkvetch rises from a taproot and can grow to 90cm across and 60cm tall. It increases with grazing and is very weedy. Flowering time happens in July as tubular and two-lipped crown appearing in a spike. The seed capsules are narrow, oblong pods with two deep grooves. Its growth resembles Narrow-Leaved Milk-Vetch (Astragalus flexuosis Dougl.), and Ground Plum (Astragalus crassicarpus Nutt.).
It thrives tremendously on soil rich in selenium and stores selenium in its tissues and emits a strong selenium odor. Livestock poisoning from selenium is famous for Astragalus bisulatus while showing no signs of damage to themselves.
Distribution
Plant grows in Arizona, Colorado, Idaho, Kansas, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, South Dakota, Utah, and Wyoming
Astragalus bisulcatus and Selenium
Two-grooved milvetch poses a very high risk of poisoning, because of its high selenium content, especially in spring. Plants are poisonous throughout the growing season with a progressive loss of selenium after flowering.
Selenium is an essential component in the diet of many animals. Concentrations of 0.3 ppm are recommended for most food producing livestock. If ingested in excess, acute selenosis and alkali disease can occur.
Significance
It has been documented that selenium contained in the plant could help prevent cancer. Two-grooved milkvetch has some ornamental value and can be found in nurseries.
Habitat Types and Plant Communities
In Utah, two-grooved milkvetch can be found at elevation from 1,460 to 2,580m. It is commonly found on dry sites, eroded banks and coulee slopes.
Name and Taxonomy
• Group: Dicotyledon
• Duration: Perennial
• Family: Fabaceae
• Genus: Astragalus
• Species: bisulcatus
o In Latin means two-grooved
• Other Names: two-grooved milkvetch, two-grooved poison vetch, and bisulcate milkvetch
Foliage
• Pinnate leaves,
• Opposite
• Hairy below
• Borne near base of plant
• Lanceolate leaflets
• 1-3 cm long
Flower
• Spike-like racemes
• 4-15 cm long
• 20-30 flowers.
• Black-hairy, lanceolate teeth on calyx
• Reddish-purple
• tubular and lipped
• 5 petals and 5 shorter sepals
Fruit
• oblong pod with two deep grooves on the upper side.
Stem
• Semi-decumbent
• Grows to 60 cm
Photosynthetic pathway
• C3