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

SUILL US

43

very long and narrow, end-cells not specialized in shape other than being
tubular. Context of floccose hyaline to yellowish interwoven hyphae.
Surface of stipe a layer of heavily incrusted hyphal tips. Clamp connections absent.
Habit, habitat, and distribution.-Cespitose to gregarious, often in
arcs and always associated with Larix (larch) as a mycorrhiza-former.
Common in the fall where tamarack (larch) grows.
Observations.-This is a common species with the pileus varying in
color from rich reddish brown to pale yellow. The slime layer is very
thick and causes a problem for any one attempting to collect this species for the table, but the species is edible.
Material examined.-Chippewa: Smith 38787, 72420. Emmet:
Kauffman 9-1-05; Smith 38823, 42924, 43107. Kent: Kauffman
9-24-04. Livingston: Smith 6065. Marquette: Mains 33-599, 33-636.
Oakland: Smith 10989, 18733, 64545, 67329. Ogemaw: Smith 50558,
50595, 67583, 67584, 67618. Washtenaw: Hintika 10-6-61, 11-3-61;
Kauffman 9-24-04, 10-19-07, 8-14-25; Mains 31-743; Smith 62308,
64589.
Section SUILLUS
Typically, the stipe is glandular dotted (in S. unicolor and S.
subaureus the glandules darken slowly and often not conspicuously, in
S. brevipes they do not show in young basidiocarps), the spore print
after moisture has escaped is typically dull cinnamon, and the pileus is
somewhat slimy. A veil may either be well enough developed to leave an
annulus, it may adhere entirely to the margin of the pileus, or it may be
absent.
Type species: As for the genus.
KEY TO SPECIES
1. Context of pileus or stipe changing to blue at least slightly when
cut..................................... S.tomentosus
1. Context not changing as in above choice...................... 2
2. Veil or false veil present (check young specimens).............. 3
2. Veil absent, the pileus margin naked or nearly so when young..... 10
3. Veil or false veil adhering to pileus margin, no remains left on the stipe
as a ring (annulus)................................... 4
3. Veil leaving an annulus on the stipe......................... 6
4. Tubes and stipe ocher-yellow; stipe 3-9 mm thick; growing under
or near Pinus strobus....................... S. americanus
4. Not as above................................... 5