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

BOLETUS

279

Tubes 5-9 mm deep, adnate to subdecurrent, dull ocher-yellow
becoming greenish yellow; pores small (about 2 per mm), dull ocheryellow, if injured staining blue readily.
Stipe 5-10 cm long, 1-2 cm thick, equal to narrowed at the base,
solid, lemon-yellow above and flavous below, rusty rose around the
wormholes. base with reddish to brownish tomentum, over most of
length the surface dull rose, ground color yellow, apex finely reticulate
for about 2 cm, below this the surface pruinose.
Spores 9-12 X 3.5-4.5 yu, smooth, lacking an apical pore, in face
view elliptic to oblong, rarely subovate, in profile suboblong to obscurely inequilateral, ochraceous in KOH, in Melzer's bluish but soon
fading to dingy ochraceous or very weakly dextrinoid.
Basidia 4-spored, narrowly clavate, 8-10 g broad. Pleurocystidia
scattered, 32-40 X 8-12 u, embedded in the hymenium or slightly
projecting, subcylindric to fusoid-ventricose, apex obtuse, content bright
yellow in KOH, walls smooth and thin. Caulocystidia mostly clavate
varying to fusoid-ventricose with obtuse apex, 26-38 X 8-16 j,, content
dull ochraceous in KOH.
Cuticle of pileus a trichodermium of hyphae 5-10 l wide, tubular
to the cylindric, clavate, oval, fusoid-ventricose or subglobose end-cell
which is yellow to ochraceous in KOH and Melzer's, content often
metallic in appearance, final differentiation of the apical cell from the
basic tubular shape often delayed until the basidiocarp is at late maturity. Hyphae of the subcutis and context with some yellow to tan
content in Melzer's but no dextrinoid incrustations present and no significant pigment dissolved in the cells. No clamp connections observed.
Habit, habitat, and distribution.-Gregarious under oak, George
Reserve, Pinckney, Livingston County, August 20, 1968, Ruth Zehner
(Smith 76042-type, and 76043).
Observations. -Collection 76042 has retained its red color in drying and very few of the terminal cells of the trichodermium vary from
the basic tubular shape. Since it has the colors of B. bicolor as dried, it
is designated the type. In 76043 the color has faded to a reddish cinnamon and more of the terminal cells are enlarged. Both, however, have
the reticulum at the apex of the stipe.
146. Boletus bicoloroides Smith & Thiers, sp. nov.
Pileus 6-15 cm latus, convexus, glaber, vinaceosanguineus tarde
obscure ochraceus. Contextus luteus. Tubuli lutei, 1.5 cm longi; pori 1-2
per mm, lutei tactu caerulei. Stipes 6-12 cm longus, 1-2 cm crassus,