[Vor. 1 
94 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
zonate or azonate, the margin very thin and acute; on the 
upper surface and at the base of the pileus a small cup-shaped 
or disk-like sterile structure is usually borne, white or brown 
and often zoned on the inside; context white, fibrous, less than 
1 mm. thick; tubes not more than 2 mm. long, at first white, 
often yellowish on drying, the mouths angular and thin-walled 
averaging about З to а mm., the dissepiments often lacerate; 
stipe (?) rudimentary, tubercular; spores not obtained. 
Growing only on fallen branches of Ulmus. Common. 
This plant has somewhat the appearance of P. pubescens 
Schum. ex Fries, from which, however, it is easily separated 
by the much thinner pileus, the attenuate base, the presence 
of the sterile cup, and the habitat. 'The cup is sometimes 
absent. Тһе development of the cup has not been closely fol- 
lowed. Lloyd believes that the fertile pileus is first developed 
and from it the sterile cup arises, and that during the winter 
the fertile portion falls away, the cup persisting on the sub- 
stratum but not giving rise to new pilei the next season. Miss 
Ames comes to the conclusion that the sterile cups represent 
pilei whose marginal hyph: have been killed by unfavorable 
conditions and which as a result may develop a fruiting surface 
from the base of the dead cup-like pileus. "This would explain 
the occasional absence of the sterile cup, its presence depending 
upon the death of the marginal hyphe in the early stages of 
the production of a first pileus. Р. virgineus Schw. described 
from North Carolina is said to be this plant. The plant is 
exceptionally well illustrated by Lloyd (Мус. Notes, Polyporoid 
Issue 3 f. 365-66), and by Moffat (Higher fungi of the Chicago 
region pl. 16. f. 2). 
7. P. pubescens Schum. ex Fries, Syst. Myc. т: 367. 1821. 
Boletus pubescens Schum. Enum. Pl. Saell. 2: 384. 1803. 
Polyporus Sullivantii Mont. Ann. Sci. Nat. II. 18: 243. 1842. 
Pileus sessile, dimidiate, 1.5-5 x 2.5-5 x 0.4-1 cm., fleshy- 
tough when fresh, firm when dry, white or yellowish in fresh 
specimens, sometimes umber or brown when dry, villous- 
tomentose, zonate or azonate, margin thin, acute; context 
white or pallid, fibrous-tough when fresh, more firm when 
dry, 1-5 mm. thick; tubes 1-4 mm. long, the mouths white, 
yellowish, or umber, angular, averaging 3-4 to a mm., the 
