It increases markedly on open grassland and woodland ranges with continued heavy grazing use by livestock and improper range management. Increase in abundance is generally accompanied by loss in grazing capacity. It differs principally in having fewer flowers in each flower head, and thus the flower heads are noticeably narrower. There are only 4 to 5 marginal flowers. Sheep, cattle, and goats are poisoned, and although death may occur, the major effect of poisoning is abortion.
Cattle are more prone to abortion than are sheep and goats.