(13) 
Neuropogon Poeppigit (Linnea, 1834, p. 495) at once from Hvernia and 
Usnea, remains good; and we may either accept the development of the 
generic conception, embarrassed though it may be by much that is still 
uncertain, in Chlorea, Nyl.; or, the rather, associating with the South 
American lichen (Poeppig. ix herb. Kunz.!) the far from dissimilar Ever- 
nia Canariensis, Mont. (Chlorea, Nyl.) prefer to refer both to an emended 
Evernia. But the other constituent of Neuropogon (N. antennarius, 
Nees et Flot.) still retained by Nylander, is, however agreeing in the 
selected characters with the first, really alien to it; and must remain, 
with whatever marked difference, in fact an Usnea (U. aurantiaco-atra 
(Jacq.) U. melaxantha, Ach.). The plant reaches its perfection only in 
the austral regions of the earth; and the arctic form (found here at Mel- 
ville Island, and in Greenland) is unknown in a fertile state. 
The species of Usnea are very widely diffused. Of the nine recog- 
nized by Nylander (Sy.) as well under Neuropogon as Usnea, three only 
of which are European, we possess six. Half of these were first described 
from North American specimens, but have proved since to have a much 
wider range.——JU. barbata, a, florida (the var. campestris, a, of Scheer. 
Spicil. p. 504) passes into a pendulous condition (v. campestris, 7, Scheer. 
1. c.) often sufficiently distinct, and recognizable as the var. ceratina ; 
which the Swiss lichenographer has perhaps well restricted to regions 
below those occupied by the other pendulous varieties. JU. trichodea, 
Ach. Meth. p. 312, t. 8, f. 1, was described from a Nova Scotia specimen, 
but has been extended by Acharius and Nylander to cover plants from 
various regions. The lichen of our northern mountains which seems 
referable here, appears tolerably distinct, though the ‘naked margin’ of 
the apothecium is not to be depended on; but southward (from New Jer- 
sey to Texas) we have another, and often larger, allied form, similar 
enough in some of its states to the northern plant, but in others approach- 
ing closely to U. longissima ; to which species indeed Nylander now (in 
Prodr. Fl. N. Gran. p. 14, not.) refers Acharius’s own JU. trichodea (L. U. 
p. 626) from the Cape of Good Hope. Both the species last-named are dis- 
tinguishable from filamentous forms of U. barbata by their always epapillate 
thallus. U. cavernosa, Tuckerm. in Agass. L. Sup., Append. (since pub- 
lished as U. lacunosa, a ms. designation of Willdenow’s, by Nylander, 
Syn.) proves to extend throughout North America, and has also occurred 
at the straits of Magellan (Commerson!) as well as in Polynesia (Picker- 
ing! in Wilkes Exped.) and in the East Indies (Herb. Hook.! Herb. Hook. 
et Thoms. n. 1718, b!). It is readily recognized by its pitted thallus. 
Radiate apothecia are probably common to all species of Usnea; and 
the character must be allowed then to possess some value. JU. trichodea 
and U. aurantiaco-atra are neither of them exceptions, as has been sup- 
posed; and the close resemblance of U. Jamaicensis to the former of 
these, and of U. Taylori, Hook. f. (the only two Usnee recognized by 
Nylander in which I have not myself observed the feature) to the latter, 
