Herbaceous, perennial weed growing 3-4 feet high 2.
Leaves are opposite, simple, ovate with sharply serrated margins.
Flowers are showy, snow white, small, in composite heads of 10-30 flowers per head. Affects all classes of livestock 2. Onset time is 2-10 days 3. Milk out lactating animals 2. Give laxatives to correct constipation 3.