Virtually everyone recognizes mature the Russian thistle, which looks like the skeleton of a normal shrub. Plants may be as small as a soccer ball or as large as a Volkswagen beetle. Most people, however, would fail to recognize the seedling and juvenile plant's bright green, succulent, grass-like shoots, which are usually red or purple striped. Mice, bighorn sheep and pronghorn eat the tender shoots. As it rolls down a desert road, a Russian thistle plants do what they do best, disperse seeds, which typically number 250,000 per plant.
Seeds are unusual in that they lack any protective coat or stored food reserves.
Instead, each seed is a coiled, embryonic plant wrapped in a thin membrane. To survive winter without a warm coat, the plant does not germinate until warm weather arrives. When moisture falls, the plant is ready to uncoil and germinate. All that is required are temperatures between 28 and 110 degrees Fahrenheit. It then quickly sends up two needle-like leaves and begins to shoot skyward.