The boletes of Michigan, by Alexander H. Smith and Harry D. Thiers.

LECCINUM

183

pseudocystidia observed. Caulocystidia mostly the fusoid-ventricose type
with elongate somewhat flexuous necks and subacute apex; clavate cells
also present.
Trichodermium of pileus appearing as an interwoven layer of subgelatinous hyphae 4-7 u wide, thin-walled, content hyaline or in a few
smoky yellowish as revived in KOH, content reddish in Melzer's in some
hyphae, end-cells tubular to somewhat cystidioid with obtuse apex.
Clamp connections absent.
Habit, habitat, and distribution.-Scattered to solitary in cold bogs,
cedar swamps, and the like, common from the Bay City-Clare line
north, late summer and fall.
Observations.-There are two variants as described in this work.
From present information both are common, but the question of one
being more frequent than the other during some seasons remains to be
studied. No "material examined" is cited because of the danger of
mixed collections. This is one of the areas in the genus still deserving
critical study.
88a. Leccinum holopus var. americanum Smith &
Thiers, var. nov.
Illus. PI. 80.
A typo differt: Contextus tactu rubellus; stipes minute punctatae,
punctae pallidae, tarde demum sordide brunneae. Specimen typicum in
Herb. Univ. Mich. conservatum est; prope Lewiston, Montmorency
County, September 7, 1967, legit Smith 751091
Pileus 5-12 cm broad, convex to broadly convex, the margin
sterile and exceeding the tubes by about 0.5-1 mm but not becoming
crenate; surface glabrous or only in age minutely areolate, dry at first,
but in age subviscid; color white when young, soon dull white to near
vinaceous-buff (over disc first), watery olivaceous over the marginal area
when water-soaked, when dried pale avellaneous (grayish) over disc and
whitish to pallid over marginal area. Context firm and white at first, the
cut surface staining reddish slowly and often developing grayish streaks;
odor and taste not distinctive.
Tubes 1-2 cm deep, deeply depressed around the stipe, becoming
wood-brown as spores mature; pores small, white at first, when lightly
bruised staining yellow.
Stipe 6-12 cm long, 10-15 mm thick, equal or nearly so, solid,
slowly staining reddish and finally pale grayish; surface pallid beneath a