Seeds: Hard and well protected by 3 stout spines. The main stem breaks when seeds are ripe and
the dried stems are curled into a loose ball; wind-blown balls spread seeds across the landscape.
Habitat: Dry, well-drained sandy, gravelly, and rocky soils on upper bajadas and moderate slopes in the mountains, especially on sandy soils derived from volcanic rocks.
Elevation: In southern Nevada, Prickly Russian Thistle occurs at elevations above 4,000 ft. Above 6,000 ft, this should be the only species present.
Distribution: Widespread throughout North America; native to Eurasia.
Comments: Called tumbleweeds because the mature plants blow on the wind to disperse seeds. A similar species, Barbedwire Russian Thistle also occurs around Las Vegas. This species is prickly from the start (seedlings prickly) and lack red on the stems.
See Beatley, J. C. (1973). Russian-thistle (Salsola) species in western United States. Journal of Range Management, 26(3), 225-226, for a good discussion of Russian-thistles in southern Nevada, or snatch a copy here (PDF). |