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

46

THE BOLETES OF MICHIGAN

brown amorphous pigment. Caulocystidia abundant, similar to cheilocystidia.
Tube trama of gelatinous hyaline hyphae somewhat divergent from
a floccose central narrow strand, the hyphae 5-9 p in diameter. Pileus
trichodermium with elements which become fused to form the squamules, these hyphae 8-12 p broad, and with end-cells somewhat cystidioid and 10-16 p broad in widest part. Clamp connections absent.
Habit, habitat, and distribution.-Scattered to gregarious under
2-needle pines, late August and early September, common during wet
seasons in its typical habitat, especially so in the pine barrens of the
Upper Peninsula as the work of Mrs. Bartelli has shown.
Observations.-In Michigan we have mostly the very pale yellow
form, but though we have studied the matter, we have been unable to
recognize any taxa that could be based on the intensity of the yellow
pigment in the pileus. The species can be quickly distinguished from S.
hirtellus and S. subaureus by the blue staining reaction of injured context. In pale forms one often finds the young pores yellow instead of
brown as described, but again, we were unable to convince ourselves
that there was a constant difference here. The species is even more
variable in the Rocky Mountains. S. variegatus in Europe is very closely
related. A critical comparative study of these two should be made.
Material examined.-Cheboygan: Smith 35834, 38368. Chippewa:
Bartelli 2420; Smith 36806, 38609, 43952, 63980, 64019. Mackinac:
Smith 8-21-53; Bartelli 2252, 251; Smith 72694, 72719. Ogemaw:
Smith 67444. Luce: Smith 38322, 42227, 42297, 58013, 58178.
10. Suillus hirtellus (Peck) Kuntze
Rev. Gen. P1. 3:535. 1898
Boletus hirtellus Peck, Bull. N. Y. State Mus. 2:94. 1889.
Rostkovites hirtellus (Peck) Murrill, Mycologia 1:14. 1909.
Ixocomus hirtellus (Peck) Singer, Ann. Mycol. 40:30. 1942.
Boletus subaureus var. siccipes Coker & Beers, Bol. North Carol. p. 83. 1943.
var. hirtellus
Illus. PI. 14 (upper fig.).
Pileus 5-10 (15) cm broad, convex with an incurved margin, expanding to plane or slightly depressed; surface at first with appressed
grayish fibrillose squamules and smaller reddish patches giving surface a
spotted appearance, ground color bright yellow with a tendency to stain
vinaceous-brown from handling, in age glabrous or nearly so, viscid when