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

BOLETUS

311

sharpen our concept of B. badius before placing American species in
synonymy with it. B. albocarneus is not closely related to B. chrysenteron. Our account is based on the original description and Smith's
study of the type; we have as yet not recognized the species in the
Michigan flora.
166. Boletus pseudosulphureus Kallenbach
Zeitsch. f. Pilzk. 2:225-30. 1923
Illus. P1. 121.
Pileus 4-9 cm broad, pulvinate to convex to broadly convex;
margin incurved slightly and sterile for about 0.5-1 mm; surface dry and
velvety when young, becoming merely unpolished and somewhat shining
by maturity; bright lemon-yellow overall varying on the disc to bright
yellow-brown ("Sudan-brown" to "Brussels-brown") and quickly blue
to indigo-black when bruised. Context lemon-yellow to greenish yellow
but instantly blue when cut, taste acidulous, odor none, with FeSO4
quickly yellow on blue surfaces, KOH quickly orange on similar surfaces.
Tubes about 1 cm deep, depressed around the stipe, bright to dull
yellow, instantly blue to greenish blue when injured; pores small (2-2.5
per mm), round to angular, bright lemon-yellow but instantly blue
where bruised.
Stipe 8-12 cm long, 1-1.5 cm thick, equal, solid, yellow within, in
age dark red in the base, quickly blue when cut; surface lemon-yellow
above a reddish base, when mature sometimes lemon-yellow overall,
smooth and merely pruinose, at times paler in lower third, soon greenish
blue and then grayish from handling.
Spore deposit "olive-brown" (dark olivaceous); spores 10-14 X
4.5-5 X 5-6 I, smooth, in face view obtusely fusoid, in profile narrowly
inequilateral wall about 1 / thick as seen in KOH mounts and golden
ochraceous, in Melzer's pale dull tan (in groups with a slight grayish
shadow).
Basidia 4-spored, 26-34 X 9-11 /u, clavate, hyaline to yellowish in
KOH and brighter yellow in Melzer's. Pleurocystidia 44-65 X 8-12,,
lanceolate to narrowly fusoid, often ventricose below, narrowed above
then ventricose again and finally tapered to an acute apex, hyaline to
yellowish in KOH and Melzer's, thin-walled, smooth.
Tube trama of very gelatinous divergent hyphae from a central
strand. Pileus trichodermium of hyphae 3-6 J in diameter, with the endcells tubular and obtuse, content ochraceous in KOH and darker dingy