General: Buffalobur Nightshade (Solanum rostratum) is a nasty, spiny weed that does not belong in the Mojave Desert. It is recognized by the yellow, or yellow and white, flowers that have fused petals and the deeply lobed leaves, In addition there are five stamens, but four are short and straight, and one is long and curved.

Buffalobur Nightshade is a common weed in the midwestern US and in coastal and central valleys of California; it is not expected in the Mojave Desert.

Keep an eye out for this species. If hikers and other visitors to the native habitats around Las Vegas see this species, please report the observation to the Nevada Department of Agriculture using their online form. Link to Weed Around Las Vegas.

Family: Nightshade (Solanaceae).

Other Names: Androcera rostrata, Solanum cornutum, Colorado bur, Kansas thistle, Mexican thistle, Texas thistle, buffalobur.

Plant Form: Upright annual.

Height: Grows to about 2-feet high.

Stems: Green, covered in long spines.

Leaves: 5-15 cm; simple, petioled; deeply lobed (more than half-way to the midrib).

Flowers: Blooms spring to fall. Inflorescence raceme-like. Flowers yellow (or yellow and white), about 1-inch across. Anthers: yellow, 4 short and straight, 1 long and curved, open at the tip. Style curved. Calyx encloses fruit, spiny.

Seeds: Fruit: berry-like capsule. Seeds small, black.

Habitat: Widespread in the west, but not the deserts. Prefers sandy soils, but grows on many soil types in disturbed areas and prairies. Drought tolerant.

Elevation: To about 1,500 feet, but found at 4,000 feet near Searchlight, Nevada.

Distribution: Across the US and south into Mexico. Native to the Great Plains region.

Comments: This species is listed as a noxious weed in Washington, Oregon, and Idaho.