Photograph from Lewis and Clark Herbarium/Academy of Natural Sciences
Lacy Tansyaster (Yellow Spiny Daisy)
Machaeranthera pinnatifida
September 15, 1804, in Chamberlain, South Dakota.
A slender plant with small, weakly bristly leaves and one yellow flower head at tip of each of many upper branches. Flower heads about 1 in (2.5 cm) wide; rays each about 0.4 in (1 cm) long, surrounding disk flowers. Leaves 0.1-0.8 in (0.3-2 cm) long, narrow. Height: 6-14 in (15-35 cm).
Open places in arid grasslands and deserts and among piñon and juniper.
Alberta, Canada, south through Rocky Mountain region and much of the Plains states to New Mexico, Arizona, southern California, and northern Mexico.