— 27 - 
On limbs of alders, Cathlamet, Wash., A. S. Foster, no. 501; and 
Comox, Vancouver Is. Macoun’s Canadian Lichens, no. 25. Plate II. Fig. 4. 
X The f. cavernosa differs chiefly from the species in color and in the depth 
attained by the cellular lacunae. While the species is also found on the 
west coast, I have examined no gradal conditions between it and the forma. 
Mr. A. S. Foster to whom I am indebted for very beautiful specimens of th® 
latter informs me that it is of rather uncommon occurrence, although when 
discovered there are usually several plants found together. 
There are certain membranaceous round or irregularly-round lobed 
conditions of C. lacunosa occasionally found that approach so nearly to 
variant examples of C. glauca as to be often confounded with that species. 
In the first mentioned the commonly brown and shining under surface is 
found to be faintly ritgose-piistulate . The C. glauca form likewise brown 
an I shining is differenced by its riigulose-reticulate \wiQX\ox The 
upper surface in both forms is distinctly lacunose-reticulate. In freshly 
gathered specimens it is easy to discriminate between the two for the C. glauca 
form has the distinct green coloration characteristic of the species, but in 
herbarium specimens where the color has changed, only attention to the 
characters below may serve to separate. 
4 . Cetraria stenophylla (Tuck.) Merrill, comb. nov. 
C. lac 2 inosa b. stenophylla Tuck. Synopsis p. 35. 
That this plant has any nearer relationship with C. lacunosa than 
C. glauca is open to question. All of the many gradal conditions of the 
species that I have examined afford evidence rather of an affinity to the 
latter through its var. b. stenophy lla Tuck. Agreeing with C lacunosa in 
coloration and in tendency to fertility, C. stenophylla is like the narrowed 
C. glaicca ioxva in mode of ramification and the more important particular 
of habit. No difficulty is experienced in tracing the origination of C. 
glauca stenophylla, for narrowed (stenophylline) states of the laciniae are 
sometimes observed as accompaniments of the typical broader ones, in a 
single individual. In no instance however have I observed any tendency of 
undoubted C. lacunosa to divide into narrowed linear lobes in the manner 
of the present. Transition states are not wanting between C. stenophy lla 
and the C. glauca form, indeed it is at times difficult to say whether a 
specimen be one or the other. The principal points of difference between 
the two may be summarized as follows. The margins of the laciniae in 
C stenophylla are commonly continuous and rather smooth, while in the 
C. glauca form they are broken, dissected and at times coralloid. C. stc7io- 
