White bursage, burro-weed
The Mojave Desert (AZ, CA, NV, UT), and adjacent areas
Sandy or rocky washes, slopes and flats, from near sea level to 4,000 feet
Up to 1.5 inches long, pinnately divided into small, rounded lobes
Stems and leaves of ambrosia dumosa, a small shrub, have a covering of soft, strigose hairs, giving them a greyish appearance. Stems are rigid and much branched, bearing alternate or (less often) opposite leaves at closely-spaced intervals. Leaves are divided up to three times into short, rounded segments, and they usually have short stalks, up to a third of an inch long.
The inflorescence is a terminal, elongated cluster of both staminate and pistillate flowerheads, subtended by narrow, pointed bracts which are initially green and flexible, but later darken in color to purple, and harden, forming a bur, enclosing the spherical fruit. Pistillate heads have just one or (usually) two florets, while staminate heads contain between 8 and 15 or more, and are subtended by one row of green phyllaries, which are fused at the base.