Hygrophorus hypothejus Fr., is another very variable plant in color as well as in size, varying from yellow, orange, reddish, sometimes paler, usually first grayish when covered with the olive colored slime. The gills are decurrent, white, then yellow. It occurs in autumn.
LACTARIUS Fr.
The genus Lactarius is easily distinguished from nearly all the other agarics by the presence of a milky or colored juice which exudes from wounded, cut, or broken places on the fresh plant. There are a few of the species of the genus Mycena which exude a watery or colored juice where wounded, but these are easily told from Lactarius because of their small size, more slender habit, and bell-shaped cap. By careful observation of these characters it is quite an easy matter to tell whether or not the plant at hand is a Lactarius. In addition to the presence of this juice or milk as it is commonly termed, the entire plant while firm is quite brittle, especially the gills. There are groups of rounded or vesiculose cells intermingled with thread-like cells in the substance of the cap. This latter character can only be seen on examination with the microscope. The brittleness of the plant as well as the presence of these groups of vesiculose cells is shared by the genus Russula, which is at once separated from Lactarius by the absence of a juice which exudes in drops.
In determining the species it is a very important thing to know the taste of the juice or of the fresh plant, whether it is peppery, or bitter, or mild, that is, tasteless. If one is careful not to swallow any of the juice or flesh of the plant no harm results from tasting any of the plants, provided they are not tasted too often during a short time, beyond the unpleasant sensation resulting from tasting some of the very "hot" kinds. It is important also to know the color of the milk when it first exudes from wounds and if it changes color on exposure to the air. These tests of the plant should be made of course while it is fresh. The spores are white, globose or nearly so in all species, and usually covered with minute spiny processes. There are a large number of species. Peck, 38th Report, N. Y. State Mus., pp. 111–133, describes 40 American species.
Figure 118.—Lactarius corrugis. Showing corrugated cap, and white milk exuding. Dark tawny brown, gills orange brown (natural size, often larger). Copyright.
Lactarius volemus Fr. Edible.—This species is by some termed the orange brown lactarius because of its usual color. It was probably termed Lactarius volemus because of the voluminous quantity of milk which exudes where the plant is broken or bruised, though it is not the only species having this character. In fresh, young plants, a mere crack or bruise will set loose quantities of the milky juice which drops rapidly from the plant. The plant is about the size of Lactarius deliciosus and occurs in damp woods, where it grows in considerable abundance from July to September, several usually growing near each other. The pileus is convex, then expanded, often with a small elevation (umbo) at the center, or sometimes plane, and when old a little depressed in the center, smooth or somewhat wrinkled. The cap is dull orange or tawny, the shade of color being lighter in some plants and darker in others. The flesh is white and quite firm. The gills are white, often tinged with the same color as the pileus, but much lighter; they are adnate or slightly decurrent. The stem is usually short, but varies from 3–10 × 1–2 cm. It is colored like the pileus, but a lighter shade.
The milk is white, abundant, mild, not unpleasant to the taste, but sticky as it dries. This plant has also long been known as one of the excellent mushrooms for food both in Europe and America. Peck states that there are several plants which resemble Lactarius volemus in color and in the milk, but that no harm could come from eating them. There is one with a more reddish brown pileus, Lactarius rufus, found sparingly in the woods, but which has a very peppery taste. It is said by some to be poisonous.
Lactarius corrugis Pk. Edible.—This species occurs with Lactarius volemus and very closely resembles it, but it is of a darker color, and the pileus is more often marked by prominent wrinkles, from which character the plant has derived its specific name. It is perhaps a little stouter plant than L. volemus, and with a thicker cap. The surface of the pileus seems to be covered with a very fine velvety tomentum which glistens as the cap is turned in the light. The gills are much darker than in L. volemus. The plants are usually clearly separated on account of these characters, yet there are occasionally light colored forms of L. corrugis which are difficult to distinguish from dark forms of L. volemus, and this fact has aroused the suspicion that corrugis is only a form of volemus.