| Russian Thistle is an annual herb that can be found in the South Texas Plains and the Edwards Plateau. It is commonly found along roadsides and in cultivated fields. It stands 1 to 2 1/2 feet tall and has leaves measuring 1/2 to 1 1/4 inches long. The stem is green with purplish-red stripes and the flowers are very small. It blooms from July to October. Russian Thistle gets its other name, tumbleweed, because when the plant dies, the stems dry inwards forming a a loose ball of branches and the plant "tumbles" along the ground with the aid of wind. The seeds may be dispersed in this way. Tumbleweed can be poisonous because it contains the toxic agent nitrate. Symptoms of nitrate poisoning include weakness, collapse, rapid breathing, dialated pupils, abortion, coma, and sudden death. |
