North American species of Lactarius / L. R. Hesler, Alexander H. Smith.

300

North American Species of Lactarius

at first. Latex white, almost instantly becoming pale lemon-yellow
when exposed to the air; taste slightly burning-acrid.
Lamellae adnate, pallid, close, narrow, some forked near the stipe.
Stipe 1.5-3 cm long and about 10 mm thick, white, hollow, hard,
the surface unpolished except for a few polished spots.
Spore deposit white; spores 6-7.5 X 4.5-6,u, ellipsoid, apiculus
oblique; wall nonamyloid; ornamentation heavily amyloid, of irregular
lines forming a broken to partial reticulum and with additional small
isolated warts present, the prominences 0.2-0.5,u high, plage area
nearly smooth and essentially nonamyloid.
Basidia 4-spored. Pleurocystidia: macrocystidia scattered to
apparently absent, 60-90 X 5-8 p, subcylindric to lanceolate; pseudocystidia 3-7 u broad, embedded or slightly projecting, filamentose,
clavate or tapered to an acute apex, many moniliform. Pileus cuticle
a thick ixocutis; hypodermium not differentiated. Stipe cuticle of repent, dry hyphae bearing subclavate caulocystidia. Rosettes few.
Habit, habitat, and distribution.-Solitary under pine, especially
Pinus banksiana, Michigan and Quebec, June-September.
Observations.-In a restudy of the type a few macrocystidia were
found. In other collections, e.g., Smith 38392 from Cheboygan County,
Michigan, scattered macrocystidia as described here were found. The
white spore deposit and slightly smaller spores are the most constant
characters for distinguishing between var. scrobiculatus and var.
pubescens. Var. pubescens appears to be the common variant of L.
scrobiculatus in Michigan, at least during some seasons. In it the
vestiture of the pilear margin is variable much as in var. canadensisfrom distinctly bearded to pubescent. It is possible that the age of
the basidiocarps and the length of time they have been standing in
the immature condition strongly influence the ornamentation of the
edge of the pileus.
Material cited.-MICHIGAN: Peters 1108 (MICH); Shaffer 3902
(MICH); Smith 38392, 38436 (type, MICH), 38437, 38594, 38753.
Canada. QUEBEC: Malloch 20.8.76/7 (TRTC).
100. Lactarius alnicola A. H. Smith
Brittonia 12: 319. 1960
var. alnicola
Illus. Smith, l.c., pl. 18. P1. 110; figs. 94, 96, 99-100.
Pileus 8-15(20) cm broad, convex-depressed with an inrolled
margin, expanding to broadly infundibuliform, "yellow-ocher" overall