Machaeranthera Bigelovii, Bigelow's Tansy Aster

Machaeranthera bigelovii, or dieteria bigelovii, is characterized by tall, rigid, branched, brownish stems bearing a sparse covering of thin leaves, topped by pink-purple flowers, each consisting of around 30 ray florets (ranging from 12 to 60) surrounding a yellow center of tiny disc flowers. The flower head is about 1.5 inches in diameter. Underneath are several rings of long, narrow, curving, green phyllaries covered with glandular hairs and sticky secretions, appearing brownish in color. The phyllaries are often visible from above, though gaps between the rays.

The plant is very similar to machaeranthera canescens, but has more limited distribution, and grows at higher elevations. Two distinguishing factors are that the bases of the phyllaries are more green in color (rather than whitish), and stickier. Also, the flower color is somewhat darker. Three varieties of machaeranthera bigelovii are recognized (mucronata, bigelovii, commixta), differing in the number of rays, number of phyllaries, and the shape of the involucre.