White burrobrush, winged ragweed
The Mojave and Sonoran deserts (AZ, CA, NV, UT), and adjacent areas
Washes, lava fields, gravelly slopes, from 700 to 6,000 feet
Alternate, thread-like, up to 2 inches long
Flowerheads of ambrosia salsola are small, and relatively short-lasting; more prominent are the fruits, which are enclosed by thin, lightly-veined wings, arranged in a whorl or spiral, initially colored white, maturing to purplish. The wings number up to 18, and are about a third of an inch long; narrow at the base and broader above. Leaves are narrow and linear, forming a tangled mass together with the slender, branched stems. The upper leaf surface has a prominent, lengthwise groove.
The inflorescence is a narrow, elongated cluster that contains both male and female flowers, on the same plant. The pistillate flowerheads contain a single floret, while the staminate flowerheads have between five and 15 florets, each subtended by between four and eight broad, equal-length phyllaries. Florets are colored dull yellow.