General: Annual, ill-scented herb from a taproot; stems erect, leafy, simple or branched, essentially glabrous, 10-60 cm tall.
Leaves: Alternate, 2-3 times divided into narrow, sparsely hairy, glandular dotted segments.
Flowers: Heads solitary at ends of uppermost branches; involucres broad; involucral bracts in several rows, overlapping, firm, narrow, with a thickened midrib and translucent margins; receptacles with papery scales only in the middle; ray flowers white, sterile and generally neutral, commonly 10-20, 5-10 mm long; disk flowers yellow, numerous.
If more than one illustration is
available for a species (e.g., separate illustrations were provided for two
subspecies) then links to the separate images will be provided below.
Note that individual subspecies or varietal illustrations are not always available.
