PAXILLUS Fr.
In the genus Paxillus the gills are usually easily separated from the pileus, though there are some species accredited to the genus that do not seem to possess this character in a marked degree. The spores are ochre or ochre brown. Often the gills are forked near the stem or anastomose, or they are connected by veins which themselves anastomose in a reticulate fashion so that the meshes resemble the pores of certain species of the family Polyporaceæ. The pileus may be viscid or dry in certain species, but the plant lacks a viscid universal veil. The genus is closely related to Gomphidius, where the gills are often forked and easily separate from the pileus, but Gomphidius possesses a viscid or glutinous universal veil. Peck in the Bull. N. Y. State Mus. Nat. Hist. 2: 29–33, describes five species.
Paxillus involutus (Batsch.) Fr. Edible.—This plant is quite common in some places and is widely distributed. It occurs on the ground in grassy places, in the open, or in woods, and on decaying logs or stumps. The stem is central, or nearly so, when growing on the ground, or eccentric when growing on wood, especially if growing from the side of a log or stump. The plants are 5–7 cm. high, the cap 3–7 cm. broad, and the stem 1–2 cm. in thickness. The plant occurs from August to October.
Figure 159.—Paxillus involutus. Cap and stem gray, olive-brown, reddish brown or tawny (natural size). Copyright.
The pileus is convex to expanded, and depressed in the center. In the young plant the margin is strongly inrolled, and as the pileus expands it unrolls in a very pretty manner. The young plant is covered with a grayish, downy substance, and when the inrolled margin of the cap comes in contact with the gills, as it does, it presses the gills against this down, and the unrolling margin is thus marked quite prominently, sometimes with furrows where the pressure of the gills was applied. The color of the pileus varies greatly. In the case of plants collected at Ithaca and in North Carolina mountains the young plant when fresh is often olive umber, becoming reddish or tawny when older, the margin with a lighter shade. As Dr. Peck states, "it often presents a strange admixture of gray, ochraceous, ferruginous, and brown hues." The flesh is yellowish and changes to reddish or brownish where bruised. The gills are decurrent, when young arcuate, then ascending, and are more or less reticulated on the stem. They are grayish, then greenish yellow changing to brown where bruised. The spores are oval, 7–9 × 4–5 µ. The stem is short, even, and of the same color as the cap.
Plate 52, Figure 160.—Paxillus rhodoxanthus. Cap reddish brown, stem paler, gills yellow (natural size). Copyright.