(98 ) 
on. Spores of the lichen of the United States rarely exceeding mmm; 
the longitudinal series of spore-cells more commonly four, but reaching 
six. In the var. microphylliwm the spores are perhaps a little smaller. —— 
15. DL. marginellum (Sw.) Mont. Trunks; Louisiana (Hale) Alabama 
(J. F. Beaumont) Texas (H. W. Ravenel). A Cuban specimen of this 
lichen is before me, which, if we except the minute wrinkling of the 
thallus (‘rides ercessivement petites,’ Mont.) presents little to distinguish 
it from L. Tremelloides beside the minute, marginal apothecia; and three 
of the four careful figures (Hoffm. Pl. Lich. t. 37, f. 1. Sw. Lich. Amer, 
t.18. Mont. Pl. Cell. Cub. t. 6, f. 2) may be said to look the same war, 
and thus to confirm Nylander’s reduction of the plant to a variety of the 
older species. But this reduction is less easy in view of other specimens 
(Wright Lich. Cub. nu. 7) the lobation of which —as suggested perhaps in 
the ‘lobis longiusculis of Acharius, and exhibited, if I mistake not, plainly 
enough by Dillenius, t. 19, f. 32,—is irreconcilable with L. Tremelloides, 
and points, not obscurely, towards Z. chloromelum. And, from this new 
point of view, we have not only a possible explanation of the narrowed, 
elongated lobes with crisped margins of the cited form of L. marginellum 
—a form which is in fact exactly repeated, in every important respect 
except the apothecia, in a North American condition of L. chloromelum 
—but can scarcely avoid associating with the former, as only a further 
development of the same lichen, the wider, scarcely crisped, and much 
more strongly wrinkled Z. corrugatulum, Nyl. (Lich. Cub. n. 6. Lindig 
Herb. N. Gran. n. 2659). As thus understood, L. marginellum partakes 
at once of the characters of, and stands between the species last preced- 
jing and the one next following; differing however, for the most part, 
from the latter, scarcely otherwise than in its extraordinary fruit-charac- 
ters. The Louisiana specimens are rather intermediate between the 
smoother, crisped form, and that exhibited in DL. corrugatilum. 
16. L. chloromelum (Sw.) Nyl. Trunks and rocks. Canada (A. T. 
Drummond). New England (Porter, &c.) common, and southward to 
Virginia. South Carolina (H. W. Ravenel). Alabama (T. M. Peters). 
Louisiana (Hale). Texas (C. Wright). The specimen figured by Swartz 
(Lich. Amer. t. 18) may be taken to explain the imperfectness of Achar- 
ius’s description of this lichen, which first found full appreciation in the 
hands of Montagne (Pl. Cell. Cuba, p. 109, t. 6, f. 1) though the latter 
afterwards confused it, in part, with his Z. Brebissonii. It is well exhib- 
ited in Wright Lich. Cub. n.8; and the same plant is most widely diffused 
in North America, and reaches even Canada. To trust indeed the evi- 
dence of my own herbarium alone, the species should rather appear a 
northern one, penetrating tropical regions, than the contrary. It is at 
any rate more difficult to discriminate the intertropical plant, lost as it 
soon is in perplexing relations to L. phyllocarpum, (comp. Lindig Herb. 
N. Gran. n. 2660, & n. 48, Coll. 29) L. Javanicum, &e. This apparent 
confusion with what are assumed to be distinct species extends also to 
