* Asclepias eriocarpa.—This is the plant with broad mullein-like leaves which is known as milkweed in California. Several authentic accounts of the poisoning of sheep have been secured against the plant in Mendocino County. It is especially feared on very warm days by sheep men when they are compelled to drive their flocks through dry, barren valleys. It sometimes grows on cultivated land, and is cut with hay.
* Asclepias syriaca.—This is the common milkweed, or silkweed, of the north-eastern quarter of the United States. Experiments show that the milky juice so abundant in all parts of the plant is very acrid and poisonous. It is listed among the poisonous plants of Europe.
SOLANACEÆ (POTATO FAMILY).
* Datura stramonium: D. tatula.—These two species very closely resemble each other, and are most commonly known in the United States by the name of jimson weed. They are European plants which have become weeds in waste grounds and about dwellings throughout the greater portion of the country. One or two instances are recorded in which cattle have been poisoned by eating hay containing the young leaves.
* Hyoscyamus niger.—The black henbane is an ill-smelling plant, a native of Europe, now naturalised in Michigan, and from New York northward. One or two cases are recorded in European literature in which stock have been poisoned by eating the plant of their own accord, but there is very little danger from it, on account of its ill odour and harsh texture.
Fig. 110.—Bittersweet (Solanum dulcamara). a, Flowering spray; b, fruit—both one-third natural size.
Fig. 111.—Black nightshade (Solanum nigrum), one-third natural size.
* Nicotiana tabacum.—This is the tobacco most commonly cultivated in the United States. It is native to South America and has escaped from cultivation to some extent in the Southern States. According to some authorities stock are not always disposed to shun this plant on account of its characteristic ill odour and taste, but, on the contrary, will eat a small amount of the leaves with apparent relish, especially when they are somewhat fresh. Stock have, however, been poisoned by eating leaves which were placed within their reach to dry, and also by eating food contaminated with the juice of the leaves. Considerable precaution should be used in applying tobacco juice to fresh cuts or bruises in stock, as the poison is easily absorbed into the system and may prove fatal. There are several native species of tobacco in the western half of the United States, all of which are undoubtedly poisonous if eaten even in moderate quantity.