Ambrosia deltoidea (Torr.) Payne

Franseria deltoidea Torr. PI. Fr£m. 15. 1853
Gaertneria deltoidea Kuntze, Rev. Gen. 339. 1891.
A shrubby perennial; branches finely tomentose at first, glabrate in age; leaves simple, petioled, finely tomentose, in age glabrate above; blades deltoid to rhombic-lanceolate, truncate or cuneate at the base, acute at the apex, crenate; heads in terminal racemes, the staminate ones several; peduncles short, 3 mm. long or less; involucre saucer-shaped, tomentulose when young; lobes 8-10, broadly triangular; paleae narrowly linear-clavate, membranous, 1-nerved, villous; pistillate heads more or less clustered on the lower part of the raceme, subtended by small ovate, mucronate or cuspidate leaves, 2or 3-flowered; fruits globose, with a turbinate base, about 6 mm. long, slightly tomentose when young, more or less glandular, 2-celled; beaks 2 or 3, subulate, about as long as the spines; spines 15-30, glandular, more or less flattened, in 2-4 series, the lower series of 8-15, very broad, leaf-like and connate at the base, straight, the upper narrower.
Type locality: On the Gila River, southern California [now Arizona].
Distribution: Southern Arizona.