Bigelow's Tansy Aster
Dieteria bigelovii
(Machaeranthera bigelovii)
Photographed along Camp Creek, Maricopa Co., Arizona. August 2008.
FLOWERS: The ray-flowers are purple to lavender-magenta. The disc
flowers are yellow. The bracts or phyllaries forming the head occur in many
overlapping series and recurve. The
peduncle is beset with sticky glands. Flowering mostly after summer
monsoon and into fall.
PERENNIAL: Mostly herbaceous above ground, but lower stems and crown may
be rather course. Plants may grow to 1.5 meters
tall with widely spreading branches.
RANGE: In the Sonoran Desert this plant tends to be found at the higher
elevations along the northeastern margins where it merges into chaparral.
ARMED. The margins of the leaves are
mucronate, but are unlikely to penetrate the skin.
LEAVES: Dark green leaves are elliptic with several, lightly spine-topped
teeth.
FRUIT: Dry single-seeded achenes are clustered in the heads and are
topped with numerous fine bristles of unequal length.