An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press




DESERT TOBACCO-Nicotiana trigonophyllaDunal

DESCRIPTION-A sticky soft hairy annual, or sometimes perennial, slightly woody toward the base, reproducing by seeds only. The stout erect stem, mostly branched above the base, is green, sticky, and densely hairy, 1 to 3 1/2 feet high. The leaves are alternate, mostly 2 to 6 (exceptionally to 10) inches long, including the stalk when present. They are broadly oblong or eggshaped, mostly pointed at the tip, but sometimes blunt. Those on the upper part of the stem are stalkless, with 2 earlike lobes at the base, while the ones below taper into a wing-edged stalk.

The tubular flowers are creamy or greenish white, 1/2 to 1 inch long, and open during the day. They are somewhat hairy on the outside, short stalked, and occur on long nearly leafless flowering branches at the ends of the stems. The calyx is 6-parted, 1/4 to 1/2 inch long, and hairy and sticky on the outer surface. It is persistent, enlarges at the base, and completely hides the mature seedpod. The smooth seedpods are many-seeded, urnshaped, and about 3/8 inch long. The tiny kidneyshaped seeds, less than 1/25 inch long, are dark or reddish brown; the surface is coarsely pitted and roughened.

DISTRIBUTION-Desert tobacco is a native range weed, most commonly found on dry sandy or gravelly soil. Widespread throughout most of the state in waste places, washes, flood plains, canyons, and water courses on desert, northern desert, woodland, and sometimes pinyon-juniper ranges; 100 to 6,000 feet elevation; flowering most of the year. Indians are reported to smoke the leaves of desert tobacco, now chiefly in ceremonials.

POISONOUS PROPERTIES-Both desert tobacco and tree tobacco contain the toxic alkaloid nicotine; the leaves and young stems are the most poisonous parts. Poisonous to all kinds of livestock and to humans; cattle and horses are poisoned more often than sheep under normal range conditions. The minimum lethal dose of desert tobacco is about 2 percent of the animal's weight on a green weight basis.

Copyright (c) 1972 The Arizona Board of Regents

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