[Vor. 1 
100 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
not been observed to be uninucleate as in that species. It 
is a large white fungus distinct from the other allied species 
in size, length of tubes, and habitat. 
17. P. obtusus Berk. Ann. & Mag. Nat. Hist. I. 3:390. 1839. 
Plants annual, sessile, sometimes imbricate; pileus dimidiate, 
convex or ungulate, 3-9 x 4-15 x 3-6 cm., somewhat spongy 
when fresh, firm, rigid, and very light in weight when dry, 
cinereous to yellowish or darker in herbarium specimens, 
hirtose-tomentose, rarely becoming glabrous, azonate, margin 
thick, obtuse; context white or whitish, spongy to согЕу, some- 
times duplex, 1-3 cm. thick; tubes 1.5-3 em. long, the mouths 
white, bay or brown on drying, circular to angular and sinuous, 
1 mm. or more in diameter; spores (teste Murrill) globose, 
smooth, hyaline, 6-8 м. 
On trunks of diseased deciduous trees, especially Quercus. 
Rare. 
Always easily recognized by the rounded and obtuse margin, 
and the long tubes with large mouths. Excellent illustrations 
are given by Spaulding (Ann. Rept. Mo. Bot. Gard. 16: pl. 13-19), 
18. P. guttulatus Peck, in басс. Syll. Fung. 6: 106. 1888. 
P. maculatus Peck, Ann. Rept. N. Y. State Mus. 26:69. 1874. 
Pileus sessile, sometimes imbricate, dimidiate, 3-8 x 5-12 
x 0.4-1.5 cm., soft and fleshy when fresh, firm and rigid when 
dry, white to yellowish or slightly brownish, glabrous, azonate 
or sometimes zonate on the margin, sometimes marked with 
rounded depressed spots, margin thin, acute; context white 
or pallid, soft and fleshy when fresh, soft-corky or friable when 
dry, 0.4-1 cm. thick; tubes 1-5 mm. long, the mouths white 
to yellowish or umbrinous, angular, averaging 4-5 to a mm.; 
spores white, smooth, oblong-ellipsoid, 2,5-3 x 3-5 u. (Cf. Mur- 
rill, globose, smooth, hyaline, 5 » in diameter.) 
Growing on wood of coniferous trees. Rare. 
The distinguishing character of the species is the presence 
of the round depressed spots on the pileus. 
19. P. borealis Fries, Syst. Myc. 1: 366. 1821. 
Pileus sessile, dimidiate, sometimes with an attenuate base, 
3-8 x 4-12 x 0.5-2.5 em., somewhat watery and spongy when 
fresh, rigid when dry, white or yellowish, sometimes brownish, 
hispid to tomentose, azonate, margin thin and acute; context 
