( 164 ) 
(ZL. subvernalis, &e., given in Wright Lich. Cub. n. 198, &c.,) it may be 
less easy to apply a different rule in the case of the Cuban lichen before 
us. —— B. milliaria (Fr., sub Lecidea, pro p., & Lich. Suec.n. 29. Bilim- 
bia, Koerb. Syst., Th. Fr. Lich. Arct.) distinguishable by its small, globular, 
black apothecia, occurs on mosses in the alpine regions of the White 
Mountains, the elongated, dactyloid or subfusiform spores varying from 
5-to plurilocula?; and on dead wood (v. ligniaria, Fr.) — when the spores 
are smaller, and commonly quadrilocular— both in the mountains, on 
charred pine stumps, and at Cambridge, Massachusetts. ——B. cupreo- 
rosella (Nyl.) Bilimbia bacidioides, Koerb. Parerg. p. 167) Lime-rocks, 
Orange County, New York (Mr. Austin). In this interesting addition to 
our species, which agrees sufficiently with the published specimen (Mass. 
Ital. n. 211, B) as with the descriptions of Koerber and Stizenberger 
(ZL. sabulet., monogr. p. 9, t. 1, B) the distinction between the present 
section (Bilimbia of authors) and the next (Bacidia) must be said to dis- 
appear; the lichen being fairly assignable to either. 
And we have thus reached, once more almost insensibly, a new, and the 
ultimate modification of the spore of Biatora,—the acicular. The con- 
tinuous series of structural variations which commences in B. vernalis, 
finds its apparent complement in B. rubella. There is no break in the 
continuity. And B. sphkeroides, taken as representative of its stock 
(stirps) as clearly passes, on the one hand into B. rubella, so taken, as, 
on the other, into B. vernalis. The just-cited description of Bilimbia 
bacidioides, Koerb., to make no other references to northern lichens, is of 
itself sufficient to indicate that Nature does not recognize these distinc- 
tions (the distinction, that is, between fusiform and acicular) here, any 
more than in Peltigera and Sticta. And it is scarcely open to doubt that 
both this species, as already remarked, and the tropical Biat. medialis 
(Obs. Lich. 1. c. 6, p. 280, and Wright Lich. Cub. n. 203, especially as com- 
pared with n. 204) are in fact equally referable to Bilimbia and Bacidia. 
But, suggestive as is the Friesian construction of B. vernalis (L. E. 
p. 260) which may well prove to have anticipated the method of much 
future study, it can hardly be denied that this group, under the micro- 
scope at least, falls readily into smaller ones; and that the integrant 
members of these are not seldom recognizable as what we call species. 
With respect however to the members of the smaller group, brought 
together, in the spirit of the same science, under B. rubella (Lecidea lute- 
ola, Prodr. p. 114) by Nylander, the case is by no means as clear. The 
tropical lichens approaching B. parvifolia, and yet more closely akin to 
B. vernalis, appear to be more distinguishable from the northern lichen, 
and from each other, than the corresponding tropical conditions associa- 
ble with B. rubella. (Obs. Lich. 1. ¢. 5, p. 279.) And the remark is per- 
haps equally true of the northern members of these groups as compared 
with their types. It is easier, in short, to look at B. rubella as a protean 
species, than as a group of species. Nor will spore-measurements, even 
