perforata. But I liave since found an isidiose specimen, otherwise 
resembling P. perlata., which may be the plant of Acharius and of 
Tuckerman’s Synop)sis which is so described. The reactions of 
I*, crinita are variously described by authoi’S as Me. Th. K. 
“saftgriin” (Krempelhuber),“atro-vii'ens fere atra,”(ihid.) Th. K-|-, 
N}^. The P. crinita Nyl. Syn. seems to be a different plant, and is 
referred by Waiuio (Brazil) partly to P. p)rohoscidea Tayl. and partly 
to P. melanothrix (Mont.) P. crinita is mentioned in several lists 
of Xorth American Lichens, but on what authority T know not. 
3. P. cetrata Ach. —This, like the preceding, is a difficult 
lichen. Tuckerman seems to have regarded all forms of the stock 
of pei'forata with narrowed or evernioid lobes as belonging here. 
But I think this can hardly be the case. P. perforata var. cetrata 
from Australia (Muller) gives Me. K.—. A remarkable variety is 
var. hypotropoides Nyl., in litt., growing on branches of red cedar at 
New Bedford, with the thallus underneath white, as in P. hypotropa., 
and becoming j^ellow with Iv. VV'ainio (Brazil) gives the reaction of 
cetrata Th. K yellow. Me. K yellow, then red, with which the New 
Bedford plant agrees. A large New Bedford plant called P. cetrata 
by 'ruckerman, is referred by Nylander to P. tiliacea., of which it 
has the lobation, but much larger spores, while it agrees with tilia¬ 
cea in its closely appressed habit. The plants called cetrata in 
lists of North American lichens must be considered as doubtful. 
4. P. saccatiloba Tayl. Nyl. Flora 188.5, p. G08, Pyr. Or. 40. 
(P. latissima Kph.; P. Zollingeri Ilepp.) — Me. K yellow, Ca Cl 
light red. Spores large, nearly as in P. latissima F6e.— Mexico. 
P. glaberrima Kph. is P. latissima Fee. 
5. P. comparata Nvl. Flora 1869, p. 290, where it is said to 
be perhaps a var. of perlata analogous to cetrata, with the aspect of 
laevigata, is said in Hue Exot. to be widely distributed in North 
America Me. K yellow. 
6. P. submarginalis Mich. Nyl. Flora 1885, p. 607, (P. per¬ 
lata Mont. Cub. 230; P. perforata var. cetrata Miiller Beitr. n. 69; 
P. perlata var. ciliata ibid. n. 1639). “Similar to P. perlata, but the 
margin of the thallus ciliate and often partly laciniate, or laciniose- 
limbriate. Apothecia larger, often perforate. Spores .014-018 x 
.008-.012'"™.” Nyl. 1. c. Me. K-. In a New Bedford specimen the 
thallus is divided into long, narrow, convex lacinim, which are 
black and naked beneath. Another old and rigid specimen was 
called P. subrugata in Willey: Lichens of New Bedford, but the 
prolonged lobes are broader.— In P. perlata the spermatia are 
bifusiform, .005""" long; in P. snbmarginalis, acieular .008-.010""" 
long, and in P. perforata acicular-cylindrical, .010-.016""" long. 
i. P. hypotropa Njd.—This species is distinguished by the 
white borders of the under side of the thallus, which are colored 
yellow then red l)y K. Keaction as in P. perforata, Me. K yellow, 
then red. 
