(165 ) 
though these represent results of a good many observations, well avail, 
where there is nothing else to rely upon. 
The Biatore with much elongated, or acicular spores, constitute the 
genus Bacidia, De Not. The group is represented by many fine, but 
closely related forms in the tropics, among which the squamulose Biatora 
microphyllina (Lecidea, Tuck. Obs. Lich. 1. c., and in Wright Lich. Cub. 
n. 211-218) an interesting analogue of B. parvifolia, in the first section, 
‘B. prasina, Mont. & Tuck., with almost filiform spores, and several inter- 
esting species from New Granada, published by Nylander (in Herb. ‘Lin- 
dig, & Prodr. N. Gran.) are especially noteworthy. But I cannot follow 
the author last named, in separating as species (Prodr. N. Gran. p. 62, 
not.) the varying conditions of B. microphyllina ; .or in distinguishing 
Lecidea millegrana (Tayl.) Nyl. (Wright Lich. Cub.n. 219. Lindig Herb. 
N. Gran. nu. 771, &c.,) from B. rubella. 
The view now to be offered of the latter species, as represented in 
North America, has not been arrived at, without repeated attempts to 
reach other results. But, conspicuously characterized as the intermediate 
conditions, supposed to be peculiar to America, undoubtedly appear, these 
are, if I mistake not, inseparable, in any large view, from the states, com- 
mon to us and Europe, which begin and end the series; and the differ- 
ences of the last from each other, however considerable, are thus, here at 
least, explained by the mediation of the first. The apothecia, which 
(typically) differ from those of B. vernalis, and B. spheroides, in being 
larger and flatter, and, in their primary condition, in an often brighter 
tint, become finally darkened, and pass into states most readily referable 
to Lecidea; the at first pale hypothecium passing also, through a not dis- 
similar series of gradations, into dark-brown, dark-claret-coloured, and 
black. In all this, no really satisfactory stopping-place offers; and should 
we attempt to keep apart from the exotic our more important American 
forms, and seek in Lecidea spadicea, Ach., the point of union of Biatora 
suffusa and B. Schweinitzit, the first of the last-named will none the less 
be found running into B. rubella, as the last into B. muscorum.. 
Biatora rubella (Ehrh.) Rabenh. (B. vernalis, a, luteola, Fr. L. E. p. 
260. B. luteola, Fr., Summ., a) has occurred to Mr. Russell, and myself, 
on Elms and on Red Cedar in New England, in a state exactly accordant 
with the European (Moug. & Nestl. n.641). But the granulose crust of this 
form becomes at length compacted even in the European lichen (Bilimbia 
rubella v. fallax, Koerb.; Stenh. Lich. Suec. n. 53, pro max. p.; and 
Biat. polychroa, Th. Fr., is perhaps another example, resembling not a 
little one of our common American forms) and this condition, with still 
large but darker apothecia, is probably what Acharius described (from 
Muhlenberg’s specimens) as Lecidea spadicea ‘apoth. Susco-badiis demum 
nigricantibus ;? and may still be called v. spadicea.’ It is far more fre- 
quent here than the other ; extending throughout the United States, and 
common also in tropical America (Wright Lich. Cub. », 220) where it 
