Machaeranthera canescens is an annual plant or short lived perennial plant in the daisy family, known by the common names hoary tansyaster and hoary-aster. It is a woolly-haired, glandular annual or perennial herb with one or more branching stems sometimes exceeding 100 cm (39 in) in height.
The inflorescence bears one or more flower heads lined with several layers of pointed, curling or curving phyllaries. The head has a center of many yellow disc florets and a fringe of blue or purple ray florets each 1 to 2 centimeters long. The fruit is an achene around 3 millimeters in length tipped with a pappus of long hairs. A number of insects can often be found in the flowers.
It is native to western and central North America, from the Pacific Coast to the Western part of the Great Plains, from British Columbia south to California, Sonora, and Chihuahua, east to Saskatchewan, the Dakotas, and Oklahoma, with a few isolated populations in Iowa and Minnesota. (Wikipedia) Photo credit: