1920] 
BURT—THELEPHORACEAE OF NORTH AMERICA. XII 197 
tomentum; no conducting organs present; cystidia rather few 
and scattered, heavily and coarsely incrusted on the peripheral 
half, conical, 30-75 X 12-25 u, usually colored under the incrus- 
tation, confined to the hymenium; slender, flexuous paraphyses 
+ » in diameter are abundant in the hymenium; spores hya- 
line, even, 44-8 X 3-4 y —but few found. 
Resupinate on under side of limbs over areas up to 25X33 
cm., and reflexed along both sides 1-23 cm. 
On under side of fallen limbs of frondose species. Florida, 
West Indies, Mexico, Colombia, and Brazil. October to May. 
Probably common. 
S. papyrinum belongs in the group with S. umbrinum and S. 
albo-badiwm; resupinate specimens of these species require ex- 
amination of sectional preparations for accurate determina- 
tion. The specimens which have been distributed by Ravenel 
and by Ellis in their exsiecati as S. papyrinum are S. umbrinum. 
In its reflexed stage, S. papyrinum is much more broadly reflexed 
than S. umbrinum and is concentrically sulcate; its cystidia are 
heavily inerusted and from 12 to 25 y in diameter by 30 to 75 u 
long, while those of S. umbrinum are much longer in proportion 
to their diameter and often can be followed from deep in the 
subhymenium, taper so gradually and bear so little incrustation, 
and are so uniformly colored that some mycologists have 
regarded them as setae, although they do not satisfy the defini- 
tion of setae. The cystidia of S. papyrinum are concolorous 
with the hyphae under the incrustation. S. albo-badium has 
cystidia heavily inerusted but smaller than those of S. papyrinum 
and not colored. 
On account of their structure, I have included in S. papyrinum 
the Cuban specimens listed by Berkeley & Curtis as S. mem- 
branaceum, for I find nothing to show that these specimens were 
ever compared with the type of the latter in Herb. Willdenow 
and collected on the Isle of Bourbon in the Indian Ocean; there 
is nothing in the original description of S. membranaceum to 
show that this may not be more closely related to S. fasciatum 
than to S. papyrinum. I have referred to S. papyrinum, as um- 
bonate-sessile forms, the specimen from Nicaragua distributed 
in Smith, Central Am. Fungi, 94, and a collection from Cuba by 
Underwood & Earle, 1584, which are cited below; these speci- 
