The increase in the number of country homes that are being built on "new land" makes important an understanding of the common poisonous plants which are likely to occur and which should not be collected for use in planting, but should rather be removed if they are so situated as to prove dangerous to people, or where they may be browsed by animals. A few of these plants are sold by growers and if planted they should be located after some forethought.
Of those in the first list there are several that are really desirable because of their flowers; but all in the second list can easily be dispensed with. Similar to the poison ivy or poison oak is the woodbine or Virginia creeper; but the latter has five leaflets on a stem while the objectionable vine has three. There are several desirable species of sumac in addition to the poisonous kind. The species to be avoided can be recognized by its growing in swamps, and it is rarely found in ground at all well drained. It and the poison ivy alike are distinguished by their white fruits. The first plant in List B, however, primula obconica, the hairy primrose, popular as a house plant, need not be discarded if any person who is susceptible to contact poisons will rinse his hands in alcohol and then wash with soap and water after handling this plant.
Where animals may browse, the planter should not place any form of the kalmia or laurel. This is the only desirable plant in List A of considerable range that grazing animals are apt to feed upon. In the west, particularly Wyoming, many sheep are killed by eating the woody aster or the death camas. The darnel poisons men, dogs, horses, and sheep, but does not harm cows, pigs, and ducks.
Of those in the first group, the mushroom is the only one that is likely to be eaten by a human being. The more dangerous species of it is the amanita phalloides or "deadly amanita," for it is widely distributed in woods and meadows and for the phallin that it contains no antidote is known. It is all the more to be guarded against in its pure white form, resembling the lepiotŠ or edible mushrooms, but, as a rule, the upper surface of the cap is grayish, brownish or greenish. (The different edible mushrooms additional to the white variety as referred to above have caps that are slaty gray, reddish brown, or brownish yellow.)
In general, it might be remarked that there is risk in taking into the system any part of a plant the properties of which are not known. The leaves of the wild black cherry, for example, are quite poisonous, especially when dried, and the seeds of the Jamestown weed are more deadly than the rest of the plant; but the physician may make proper use of belladonna, strychnine, and aconite.