Lichenes of New England. 443 
aleurites, Ach. Prodr., Lichen diffusus, Dicks. — Old 
rails; Cambridge, and elsewhere, not very uncom- 
mon 
|. P. erinita, Ach. Syn. (cit. Hals.) Muhl. 1. c., ‘Torr. 
l.c., Hals: l. c., Mass. Catal. (with a qu.) — Trunks, 
and stones. Acharian woods, Cambridge ; and else- 
where, not uncommon. One of the largest and finest 
forms of the genus. Our plant is probably that no- 
ticed by the above authors, and it is peculiar to the 
North American Flora. Muhlenberg notes it “N. S$.” 
in his catalogue, from which we may infer that it 
was one of those which he discovered and sent to 
Acharius. The apothecia seem to be wholly unno- 
ticed, both in the brief description of Halsey, and in 
the longer one given in Eaton's * Manual.” These 
commonly occur at the Cambridge station of our 
plant, and are well worthy of notice. They become 
very large, rufous, with margins irregularly lacerated, 
and beset with the same coral-like branched apophy- 
ses, which form so remarkable a feature (distinguish- 
ing also several other allied American species, ) of the 
upper surface of the thallus. 'These apothecia are 
near the margin, and sub-pedicelled, and much re- 
semble those of P. perforata, with which spoori our 
Pait, in habit, generally agrees. 
- P. stellàris, p. aipólia, P.aipolia, Ach. Meth. p. 209., 
Lichenogr. p. 477., Scher.! 1. c., Muhl. 1. c., Mass. 
Catal., P. homochroa, $. platyphyllina, Wallr. 1. c., 
Lichen aipolius, Ach. Prodr. — Trees and old rails, 
Cambridge, and elsewhere, common. Sprengel does 
not allow this even the rank of a variety. Our plant 
seems to agree with Scherer’s specimens, and to 
