AMBROSIACEÆ (RAGWEED FAMILY).
Xanthium canadense.—The young seedlings of the American cocklebur are reported from Texas as being rapidly fatal to hogs.
Xanthium spinosum.—The spiny clotbur is suspected of being poisonous, but few cases have been definitely recorded against it. The seeds apparently contain a toxic compound.
Xanthium strumarium.—The young seedlings of the broad cocklebur are reported from Georgia as being fatal to hogs. Experiments seem to show that the seed is poisonous.
CARDUACEÆ (THISTLE FAMILY).
* Helenium autumnale.—Sneezeweed (sneezewort; autumn sneezeweed; stagger weed; false sunflower) is found throughout the greater portion of the United States, being most abundant in the Southern and Eastern States. Sheep, cattle and horses that are unfamiliar with the plant are often poisoned by it when driven to localities where it is abundant. Stock avoid it, as a rule, but it is claimed that they sometimes develop a taste for the plant, and are killed quickly by eating it in large quantity.
Senecio jacobæa.—The tansy ragwort, or stagger wort, is a European plant which grows as a weed in ballast about New York and Philadelphia. Farther north, in Nova Scotia, it has become extensively naturalised, and it is there regarded by stock men as poisonous. It is interesting to note that S. guadalensis of Mexico is also considered fatal to stock.
COLCHICUM POISONING.
Fodder of bad quality often contains leaves, flowers, and particularly seeds of colchicum, which produce nausea, vomiting, colic and diarrhœa. The colchicine acts particularly on the kidney and heart, producing specific disturbance, indicated by hæmaturia, polyuria, and cardiac palpitation, with lowering of the body temperature.
Even when poisoning is not fatal, it is very apt to produce abortion.