Case'S Milkvetch

astragalus casei

Case's Milkvetch (Astragalus casei) is a distinctive perennial herb belonging to the expansive pea family (Fabaceae), known for its resilience in arid and semi-arid environments of the western United States. This unassuming yet vital plant plays a crucial ecological role, often found clinging to rocky slopes and sandy flats where other vegetation struggles. It is characterized by its sprawling growth habit and delicate, pea-like flowers, which bring subtle beauty to harsh landscapes. Like many of its legume relatives, Astragalus casei is capable of nitrogen fixation, enriching the soil and supporting a complex web of life in its native habitats. Its hardy nature and unique adaptations make it a fascinating subject for botanists and a significant component of the local flora.

Habitat: Case's Milkvetch thrives in dry, open habitats, including sagebrush scrub, pinyon-juniper woodlands, and rocky slopes with sandy or gravelly, often volcanic, soils at elevations ranging from 1,200 to 2,800 meters.

Appearance

This perennial plant typically forms low, matted growths, often appearing somewhat sprawling or cushion-like. Its leaves are pinnately compound, meaning they consist of multiple small leaflets arranged along a central stem, often with a silvery-green or gray-green hue due to fine hairs. The flowers, emerging from short stalks, are typical pea-shaped blossoms, usually purplish, pinkish, or sometimes cream to whitish, arranged in short, dense clusters. After flowering, it produces distinctive, often inflated or leathery, pea-like pods (legumes) that contain its seeds, which are a key identifier for the genus. The plant generally reaches a height of 10-30 cm.

KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderFabalesFamilyFabaceaeGenusAstragalus

Case'S Milkvetch

Interesting facts

Case's Milkvetch is an important food source and habitat component for various native insects and small mammals in its arid ecosystem.

Many milkvetch species are known for producing a potent neurotoxin called swainsonine, which can be harmful to grazing livestock, though not all species are toxic.

The Fabaceae family, to which Case's Milkvetch belongs, is the third-largest family of flowering plants, with over 19,000 species worldwide.

The genus name Astragalus is derived from the Greek word for ankle bone, possibly referring to the shape of the seeds or pods of some species.

Special abilities

The plant forms a symbiotic relationship with specific soil bacteria in its root nodules, allowing it to convert atmospheric nitrogen into a usable form, enriching nutrient-poor soils.

Adaptations such as a deep taproot system and potentially hairy leaves help reduce water loss, enabling it to survive prolonged dry periods in arid environments.

It is specifically adapted to grow in challenging substrates like volcanic ash, gravelly flats, and sandy soils, where competition from other plants is limited.

Measurements & details

Length: 10-30 cm
Weight: 0.01-0.1 kg
Lifespan: 3-10 years
Clutch Size: 50-500

Diet & Feeding

Case's Milkvetch, as an autotrophic plant, produces its own food through photosynthesis, converting sunlight, water, and carbon dioxide into sugars. It also absorbs essential mineral nutrients from the soil via its root system.

Primary Foods

Sunlight
Water
Carbon Dioxide
Nitrogen
Phosphorus
Potassium

Foraging Method

Nutrient Absorption

Ecological connections

mutualism

Western Bumblebee

Bombus occidentalis

Pollinates flowers

eaten by

Mule Deer

Odocoileus hemionus

Herbivory on foliage and seeds

mutualism

Rhizobium bacteria

Rhizobium leguminosarum

Nitrogen-fixing symbiosis

host plant

Western Tailed-Blue

Cupido amyntula

Larval host plant

Traits

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Also known as

No aliases listed yet.

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Case'S Milkvetch?

The easiest way to identify Case'S Milkvetch is to use the Snappit nature identifier app.

How long is Case'S Milkvetch?

10-30 cm

How much does Case'S Milkvetch weigh?

0.01-0.1 kg

How long does Case'S Milkvetch live?

3-10 years

What does Case'S Milkvetch eat?

Where is Case'S Milkvetch usually found?

Case's Milkvetch thrives in dry, open habitats, including sagebrush scrub, pinyon-juniper woodlands, and rocky slopes with sandy or gravelly, often volcanic, soils at elevations ranging from 1,200 to 2,800 meters.

How does Case'S Milkvetch hunt?

Nutrient Absorption

How many eggs does Case'S Milkvetch lay?

50-500