(20) 
and to reduce the group to modifications of but two specific types; T. pa- 
rietinus reclaiming T. candelarius, and T. chrysophthalmus being forced 
to include the whole of the ascendant cluster ;— but no doubt this criti- 
cism has its rights. It appears impossible, in any large view, to extricate 
“ Physcia flavicans” from the web of recognized varieties of T. chrysoph- 
thalmus; or clearly to distinguish Physcia hypoglauca, Nyl. (Lindig 
Herb. N. Gran. n. 22, 2595) however interesting in its spores, from the 
same. And Dufourea flammea, Ach. (Physcia, Nyl.) as exhibited in the 
instructive specimens of Drége, and interpreted by Laurer (Herb. Sonder) 
is only an instance in the present genus, and in 7. purietinus, of a thal- 
line anomaly, of which both the next succeeding genera exhibit marked 
and yet satisfactorily determinable examples. Nor is this the only proof 
that the foliaceous centre of Theloschistes is itself conditioned by the 
same nisus to ascend which marks the whole group; and relates it so 
intimately to the Usneei. 
The species, etc., reckoned in the author’s Synopsis, were revised in 
Obs. Lich. (1. c.) and those added which are found only southward of the 
limits of the earlier enumeration. Among these are the elongated condi- 
tions of ZT. chrysophthalmus (Borrera pubera, and B. flavicans, Ach.) 
which, as respects the pubescent state, and the wholly smooth and esore- 
diate one, are confined to our extreme southern States and California; 
where only, with us, the lichen is fertile. Sorediate (sterile) forms, which 
are not deficient at the south (Galveston Bay, Texas, Mr. Ravenel) occur, 
however, also far northward (Nantucket, myself; and even Newfound- 
land, Nyl. Sy.) but without doubt only in maritime districts ——T. pari- 
etinus, V. lychneus, occurring with us precisely as in Europe (Physcia 
controversa, Mass., Koerb. p. 38) is a well-marked and elegant lichen, al- 
most as deserving of specific distinction, one should say, as T. candela- 
rius; but yet running very close, in its narrower and smoother state, to 
the v. polycarpus of the species first named. —— 7. parietinus v. Fin- 
markicus. Ach., (Borrera pygmea, Bory) commonly associated, as, an 
ascendant form, with the variety just considered, has occurred in Alaska 
(Dr. Kellogg) and proves to be common on the coast of California (Bo- 
lander. T. parietinus v. ramulosus, Tuckerm. Lich. Calif. (Physcia 
pariet. v. ramulosa, Obs. Lich. 1. c.) is a curious and easily distinguish- 
able Californian lichen, combining, with semi-terete lobes, much of the 
aspect of 7. candelarius with the thekes and spores (and chemical reac- 
tion, with potash) of T. parietinus. 
X.—PARMELIA, Ach., De Not. 
Parmelia, De Not., cit. Mass. Mem. p. 48. Th. Fr. Lich. Arct. p. 51; 
Gen. p. 58. Mudd. Man. Brit. Lich. p, 92. Parmeliz spp., et Borrere, 
Dufouree, et Cornicularie spp., Ach. L.U., Syn. Parmelia sect. Im- 
bricaria (spp. citrin. excl.) Fr. L. E. p. 57. Tuckerm. Syn. N. Eng. 
