General: Mojave Thistle (Cirsium mohavense) is a two-year or short-lived perennial that spends the first year as a rosette of spiky leaves. In the second year, it sends up a flower stalk with spiky leaves and topped with a spike-protected whitish flowerhead. This species is recognized by the small heads bearing pale lavender flowers.

Around Las Vegas, Mojave Thistle is an uncommon component of vegetation communities in moist soils around desert springs, streams, and ditches in the Lower Sonoran (Creosote-Bursage Flats) and Upper Sonoran (Mojave Desert Scrub) life zones. Look for Mojave Thistle at Calico Basin and other springs in the Red Rock Canyon NCA area.

Family: Sunflower (Asteraceae).

Plant Form: Basal rosette, then upright stalks topped with flowerheads

Height: To about 7 feet.

Stems: Usually a single main stem that branches above to a few stems.

Leaves: Green with woolly hairs (tomentose) especially on the underside of the leaf. Basal leaves 4-8 inches, long and narrow with spiked lobes. Upper leaves few, small, spiny. Main spines on leaves to almost 1 inch.

Flowers: Blooms in the summer. Inflorescence: flowerhead formed of many flowers. Flowers emerge from a round, spiky ball (involucre) that only gets to about 1-inch diameter (small for a thistle); involucre spines to about 1/3-inch. Flowers white to lavender.

Seeds: achene.

Habitat: Damp soils around desert springs, streams, and ditches.

Elevation: 1,500 to 9,000 feet.

Distribution: California, Nevada, and Arizona.

Comments: The seeds of thistles are a favorite for American Goldfinches and Lesser Goldfinches, who usually delay breeding until the seeds are ready to eat.