An Illustrated Guide to ARIZONA WEEDS
The University of Arizona Press
FRINGED PIGWEED-Amaranthus fimbriatus (Torr.) Benth.
DESCRIPTION-An erect annual, sometimes bushy with many branches, 1 to 2 (or 3) feet high. The leaves are alternate, lanceshaped or somewhat eggshaped, and pointed at the top. They have smooth edges and a short stalk, 1 to 2 inches long.
The small flowers are of 2 kinds, male and female, with both kinds on the same plant. The male flowers are few, and occur together in clusters in the leaf axils, at the stem tips, and at the top of the plant in long nearly leafless spikes. The many female flowers are very conspicuous and pretty at maturity. The 5 flower parts enlarge, and each spreads out above into a thin pinkish white papery fanshaped structure, the edges of which are slightly fringed. This structure encloses the little thin-walled fruit, whose top falls away as a lid, shedding the tiny seed when it is mature. The oval seed is shiny, reddish black, and about 1/25 inch in diameter.
DISTRIBUTION-Fringed pigweed is a southwestern native plant, growing in dry sandy or rocky soil of desert washes, mesas, and roadsides. It has spread into the cultivated fields, particularly in newer agricultural areas, as in Avra and Yuma valleys; common throughout southern Arizona; northward to Mohave and western Coconino counties; 100 to 4,000 feet elevation; flowering July to October.
Copyright (c) 1972 The Arizona Board of Regents