Racemose Milkvetch

astragalus racemosus

Racemose Milkvetch (Astragalus racemosus) is a robust, perennial wildflower native to the open prairies and badlands of central and western North America. Belonging to the diverse Fabaceae family, this species is highly specialized to thrive in soils that many other plants find inhospitable. It is famously classified as a selenium hyperaccumulator, meaning it actively draws up large concentrations of selenium from the ground, storing it within its tissues. While this adaptation renders the plant highly toxic to grazing livestock, it serves as a critical defense mechanism against hungry herbivores in the wild. This fascinating survival strategy makes it a key subject of ecological study. Its dense, drooping clusters of creamy-white flowers provide crucial nectar for native bumblebees, demonstrating its complex role as both a localized hazard and an ecological partner. If you want to identify Racemose Milkvetch in the wild, use the Snappit app.

Habitat: Found on open prairies, plains, clay badlands, and roadsides, typically growing in heavy, clay-rich soils high in selenium or gypsum.

Appearance

This upright perennial typically grows between 30 to 100 centimeters tall, forming leafy clumps with sturdy, sometimes reddish-purple stems. Its leaves are pinnately compound, divided into numerous narrow, oblong leaflets of a grayish-green hue. The most distinguishing feature is the dense, one-sided clusters (racemes) of tubular, pea-like flowers. These blossoms are creamy-white to pale yellow, measuring about 1.5 to 2 centimeters long, and they hang gracefully downward from long stalks. After flowering, the plant produces swollen, triangular seed pods that dry to a light brown color.

KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderFabalesFamilyFabaceaeGenusAstragalus

Racemose Milkvetch

Interesting facts

Because it only grows in soils rich in selenium, uranium prospectors historically used the presence of this plant to locate uranium-bearing geological formations.

It is highly toxic to horses and cattle, causing a chronic poisoning known as 'alkali disease' or 'blind staggers,' which leads to hair loss and hoof deformities.

When bruised or growing in hot weather, the plant releases a strong, garlic-like odor due to its high concentration of volatile selenium compounds.

Special abilities

Actively absorbs and concentrates selenium from the soil, making its tissues toxic to herbivores and reducing competition from sensitive plants nearby.

Partners with specialized underground rhizobia bacteria to convert atmospheric nitrogen into nutrients, enriching poor prairie soils.

Employs a deep, robust woody taproot that anchors the plant and accesses deep water reserves in arid grasslands.

Measurements & details

Length: 30-100 cm
Lifespan: 3-10 years

Diet & Feeding

As a photosynthetic autotroph, it synthesizes its own sugars using sunlight, carbon dioxide, and water while absorbing essential minerals from the soil.

Primary Foods

Sunlight
Carbon Dioxide
Water
Soil Minerals

Ecological connections

mutualism

Rhizobium bacteria

Rhizobium leguminosarum

Forms a mutualistic relationship in the root nodules to convert atmospheric nitrogen into usable ammonia.

mutualism

Hunt's Bumblebee

Bombus huntii

Feeds on the nectar of the flowers while acting as a primary pollinator.

eaten by

Astragalus Seed Beetle

Acanthoscelides aureolus

Larvae of this beetle feed directly on the developing seeds inside the woody pods.

Traits

No trait badges are assigned for this object yet.

Also known as

No aliases listed yet.

Collections

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Racemose Milkvetch?

The easiest way to identify Racemose Milkvetch is to use the Snappit nature identifier app.

How long is Racemose Milkvetch?

30-100 cm

How long does Racemose Milkvetch live?

3-10 years

What does Racemose Milkvetch eat?

As a photosynthetic autotroph, it synthesizes its own sugars using sunlight, carbon dioxide, and water while absorbing essential minerals from the soil.

Where is Racemose Milkvetch usually found?

Found on open prairies, plains, clay badlands, and roadsides, typically growing in heavy, clay-rich soils high in selenium or gypsum.