(96 ) 
Willer). New Jersey (C. F. Austin). Ohio (Lea). Tlinois (E. Hall). 
Islands of Behring’s Straits (C. Wright). Much more rarely on trunks ; 
Massachusetts (H. Willey). All our plants, the longitudinal series of 
cells in the spores of which are commonly six to eight, though sometimes 
scarcely exceeding four, appear to be strictly associable in a single 
species, and not to differ from Zw. ers. n. 175, both specimens of which 
are cited by Nylander; and Nyl. Lich. Paris.n. 2.—L. pusillum, NY1., 
and L. spongiosum, Nyl., are other minute species, as yet unknown here. 
—— 6. L. minutissimum, Floerk.; Moug. & Nestl. n. 1239; Anz. Lich. 
Langobvard. n. 411; Arn. Fragm. in Flora, 1867, p. 121, t. 1, f. 10-16. 
On the earth, Illinois, E. Hall. I cannot but keep this apart. Spores 
ZPumm; the longitudinal series of spore-cells four to five. Thallus 
much more developed than in L. subtile, and rather approaching that of 
the next species, with which Nylander has united L. minutissimaum.—_— 
7. L.lacerum (Sw.) Fr. Rocks, common. Canada (A. T. Drummond). 
New England (J. L. Russell). New York to Maryland. Ohio (Lea). A 
much dissected form (Vv. oph@um) is not rare, and one with terete branch- 
lets (v. bolacinum, Scher.? but the same with Lich. Helv. n. 407, dextr., 
in my copy) occurs. ——8. LZ. scotinum (Ach.) Fr. On rocks, Auburn, 
and in the Yo Semite valley, California (H. N. Bolander). The group of 
lichens referred here is readily distinguished from ZL. lacerum by the 
darker coloration, and in part also by entire, or only notched lobes. The 
range of variation, though to a considerable extent similar to that indi- 
cated by my European specimens, is however greater, and ends in nar- 
rowed forms comparable only with the var. lopheum of the next prece- 
ding species. But even these forms are at least suggested by some 
European ones (Coll. scotinum, Sauter in herb. Krempelh.) and the widest 
state of our plant (v. platynum) may be said to differ from such condi- 
tions as Nyl. Lich. Paris. n. 101, much as the Californian L. albociliatum 
from the cited European; oras LZ. tremelloides vy. azureum from the v. 
cyanescens, and v. minus. Spores of the Californian lichen =? mmm, 
agreeing in all respects with those of the foreign plant; which, like L. 
albociliatum, and the species immediately following, is not known to be 
elsewhere exhibited in North America. —-9. L. palmatum (Huds.) 
Mont. Rocks; coast of California (Menzies; H. N. Bolander). North 
West coast, 49° N. lat. (Dr. Lyall). Spores #8mmm.; the longitudinal 
series of spore-cells oftener ten. The species is evidently akin to the 
next preceding. 10. L. Apalachense (Tuck.) Nyl. Syn. p. 133. Col- 
lema, Tuck. Suppl. 2, 1. c. 200. Caleareous rocks, Alabama (T. M. 
Peters). On similar rocks in Missouri (E. Hall). Cortex ill-developed; 
and the lichen is in all respects quite isolated as respects American 
species, but is well compared by Nylander with the European L. 
Schraderi, ——11. L. dactylinum, Tuckerm. Obs. Lich. 1. c. 4, p. 383. 
Nyl. Syn. 1, p-123. Rocks (caleareous schist) Brattleborough, Vermont 
