|Scientific Name||Xanthisma spinulosum var. chihuahuanum
(Machaeranthera pinnatifida var. chihuahuana)
|USDA PLANTS Symbol||MAPIC|
|Common Name||Chihuahua Tansyaster||ITIS Taxonomic Serial No.||780983|
|Family||Asteraceae (Sunflower)||Flora of North America Ref.||Click Here|
|Description||Habitat: Clay or rocky soils in washes, prairies and roadsides; desert environment.
Plant: Erect perennial 12 to 20 inches tall; multiple tangled smooth or slightly hairy stems from woody base.
Leaves: Numerous stem leaves, usually somewhat hairy, 1 to 3 inches long; lower leaves lanceolate overall, pinnatifid lobes with spines at lobe tips, central portion much wider than lobes; upper leaves with few or no lobes, becoming linear-oblong, tips rounded with short spines.
Inflorescence: Terminal, compound yellow flowers about 1 inch or less across; 14 to 60 rays and 30-plus yellow disk florets; phyllary tips not bent and do not have a spine.
Bloom Period: Spring to fall.
References: American Southwest, Flora of North America and Machaeranthera pinnatifida in "Manual of the Vascular Plants of Texas" by Correll and Johnston.
Notes: Xanthisma spinulosum is a highly variable species with several variants, chihuahuanum being found in the Chihuahua desert (including portions of Big Bend). Some of the variations occur in the leaves and the degree to which the margins are lobed, and the presence, or lack of, small spines on the phyllary tips.
|BONAP Distribution Map
Map Color Key
Banner photo of Lupinus ssp. by Rick Capozza, Austin TX
© Tom Lebsack 2023