This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Xylorhiza Parryi, Gray Native. Perennial. Propagates by seeds.
Time of bloom: Late May to June.
Seed-time: June to early July.
Range: Western Wyoming, Colorado, and adjacent Utah.
Habitat: Alkaline clay soil; range pastures.
A most pernicious plant, because of its extremely poisonous properties. A bulletin of the State Experiment Station of Wyoming is authority for the statement that, in the sheep-raising industry alone, that commonwealth suffers a yearly loss of more than three million dollars, the greater part of which is due to poisonous plants on the pasture ranges, this weed being considered by many stockmen the most noxious of all, since at least 90 per cent of the animals affected die.
Roots thick, strong, woody, branching more or less just at the surface of the ground; from these branching, woody crowns rise tufts of short branches, four to eight inches in height, forming a dense, crowded stool. Leaves alternate, one to two inches long, spatulate-linear, sessile, entire, light green, somewhat hoary with a thin, soft woolly-hairiness; usually they are spotted with a brown fungus. Heads solitary, terminating the numerous young branches, an inch or more broad, with many white rays and yellow disks; bracts of the involucre oblong lance-shaped, keeled below, long-pointed, covered with ashy-gray hair. Achenes white-hairy, with a bristly, yellowish pappus. When green and growing, the whole plant gives off an unpleasant odor and has a bitter taste. After the flowers mature the plant withers and dries, becoming yellowish brown in color and losing its noxious qualities, as thereafter the sheep feed freely on the dried herbage without apparent harm. (Fig. 299.)
Fig. 299. - Woody Aster (Xylorhiza Parryi). X 1/4.
Herding the animals away from localities where the plants are abundant, during the noxious season of green leafage and bloom, seems to be the only practicable plan under existing conditions. But it would seem that so tremendous an injury to so important an industry should be a matter of interest to the entire community, better met by concerted communal action than by individual effort, and that yearly a large portion of the land cursed by such deadly herbage might be redeemed from it, supplanting its bane with wholesome growth, if merely salt-bushes.