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

520

North American Species of Lactarius

ing a more inconspicuous reticulum by bridging the heavy lines, or
the finer lines simply appearing as tails from the major elements;
large and small isolated warts also present, prominences up to I g.
high, the bands 0.5-1 jL wide; plage area nearly smooth and lacking
a diffusely amyloid spot.
Basidia 28-35 X 8-10 uL, 4-spored, hyaline in KOH. Pleurocystidia: macrocystidia 42-63(80) X 4-8 L, scattered but conspicuous,
projecting 15-40 p., aciculate to ventricose, content amorphous, reticulate and refractive; pseudocystidia scattered, cylindric or flexuous,
hardly projecting from the hymenium. Cheilocystidia 30-40 X 2.5-5 t,
similar to the pleurocystidia. Subhymenium filamentose-interwoven,
the hyphae much-branched and 3-6 1A in diameter; mediostratum of
gills of interwoven connective hyphae and lactifers; no sphaerocysts
evident. Pileus cuticle of clavate, vesiculose, cuneiform, and sausageshaped cells intermingled to form a distinct layer, hyaline in KOH and
breaking up to form mounds as the mature pileus fades. Pileus trama of
interwoven connective hyphae, lactiferous hyphae and some sphaerocysts. Stipe cuticle of dry, repent hyphae; rosettes present in cortex.
Habit, habitat, and distribution.-Gregarious on sphagnum, in
bogs, Michigan and Canada, August and October.
Observations.-The cuticular elements on the pileus are inflated
cells of various shapes. The mounds are readily demonstrated on
mature faded pilei. The spore deposit is white to off-white but not yellow and the taste is mild. Our previous (1960b) report of a slightly
acrid taste (Smith 37095) has not been verified by subsequent collections with all developmental stages present. The latex was critically
studied by Weber (Weber 3992) and no change to yellow took place,
and white paper was not stained yellow. In some other collections
(Weber 4075 and Smith 85366 and possibly in Smith 85369) a slight
yellowing occurred on white paper after several hours. In view of our
more recent studies we regard the species as related to but amply distinct from L. thejogalus. The spore ornamentation readily distinguishes them. L. tabidus sensu Neuhoff (1956) has yellow spores ("C")
and a browner stipe. L. canadensis, however, appears to be the counterpart of L. tabidus in Europe.
Material cited.-MICHIGAN: Nimke 617 (MICH); Smith 39138
(type, MICH), 50348, 63975, 64015, 80875, 84520, 84738, 85366, 85367,
85369; Weber 3992, 4074, 4075 (all MICH).
Canada. ONTARIO: Smith 4020, 4058.
196. Lactarius thejogalus (Fr.) S. F. Gray
Nat. Arr. Brit. Pls. 1: 624, 1821

Agaricus thejogalus Fr., Syst. Mycol. 1: 71. 1821.
Lactarius isabellinus Burlingham, Bull. Torrey Bot. Club 34: 88. 1907.