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

G YROPOR US

31

"barium-yellow" to "seafoam-yellow") at maturity, unchanging when
bruised or merely changing to brownish; pores typically small (1-2 per
mm), round to angular, in very old basidiocarps more angular and up to
1 mm diameter, not staining when bruised.
Stipe 3-7 (9) cm long, 6-8 (15) mm thick at the apex, about 2.3
cm near the base, often pinched off at the base, equal to slightly ventricose or subclavate, hollow in lower portion at least in age and very
fragile, surface dry, unpolished, glabrous, colored evenly like the pileus
or paler above ("cinnamon-buff to "cinnamon"); veil absent.
Spore deposit a clear light yellow ("pale lemon-yellow"); spores
8-12.6 X 5-6 J, smooth, lacking a germ pore, ellipsoid to occasionally
ovoid, with a distinct hyaline sheath, pale tawny in Melzer's, nearly
hyaline in KOH, relatively thin-walled.
Basidia 30-36 X 9-12 L, clavate, 4-spored, yellowish hyaline in
KOH. Cheilocystidia abundant, narrowly fusoid, 30-40 X 6-9,, hyaline
in KOH, nonamyloid, thin-walled, smooth. Tube trama divergent and
only subgelatinous, nonamyloid, hyphae about 7 j broad.
Pileus cuticle a turf of pileocystidia often as terminal cells of short
hyphae (cuticle basically a trichodermium), 50-72 X 8-16 J, gradually
tapered to an obtuse to subacute apex, hyaline in KOH, smooth, thinwalled, the penultimate cells about half the length of the terminal cell,
the cells near the base of trichodermial element often greatly inflated;
walls smooth and nonamyloid, content not colored in Melzer's. Context
of floccose interwoven hyaline hyphae, walls smooth and nonamyloid
and content as revived in Melzer's not colored. Stipe surface with
hyphae having numerous hyaline sausage-shaped cystidioid end-cells
somewhat appressed to projecting. Clamp connections present, but many
pseudoclamps also present.
Habit, habitat, and distribution.-Single to scattered or gregarious
in open oak and in mixed conifer and hardwood forests during late
summer and early fall. It is fairly common in southern Michigan.
Observations.-Within the color range given in the description there
may be several constant races occurring in our region. These should be
restudied from fresh material in order to evaluate properly their status
as taxa. In most herbarium material there are not sufficient notes with
the specimens to contribute much toward such a study. We have, for
instance, a large form in the state with a stipe 3 cm or more thick at
the apex, but so far we have found only rather old or weathered specimens.
Materials examined.-Barry: Smith 72965, 73104. Cheboygan:
Smith 57398, 58291, 61428, 63103; Thiers 3454. Emmet: Kauffman