350 
trees ; 13, or a little more than 9 per cent., are found growing on 
earth, and two species are parasitic. On the other hand, if we 
compare the Black Hills list with one by Henry Willey, based 
upon collections made in the Rocky Mountains by Dr. Coulter, 
found in the report of the latter in the United States Geological 
Survey of the Territories, we find a greater similarity, so far as 
distribution is concerned. In this case 34, or about 52 per cent., 
were collected on rocks; 18, or nearly 28 per cent., on earth; 12 
or more than 18 per cent., on trees, and a single species on both 
trees and rocks. These numbers may be readily followed out in 
_ the appended table: 
——— 
NUMBERS. PER CENTS. 
ue i 
a a a ic a. 
eo po ol ede ee oe 
HABITAT. ss - = = 
ne 5 eee 2 z 
eee | So tg | ee 
ea) aa Z aa] a = 
i Wet ol a ee ea 8 | 68 12 10 58 18 
OR FOC ee rs 44 32 53 28 Sf 
On trees.and récks) 32s ae HE Bae aN I ‘ Me eee 
in Matta oo fi en eens eee SW | ele 9 | 8 
On'earth and rocks, 2 See I a goed pois ep Eee ee 
On Garth and: wood... eee: I poy Se pe 
POTASING sO Ge es ee I 2 pth 
Tres ee ee 
Twenty-five of the lichens found in the Black Hills are found 
also in Eastern Nebraska and 20 are found in the Rocky Moun- 
tains, while the Rocky Mountain list contains 16 species found in 
Eastern Nebraska. Nine forms are common to the three regions. 
It would seem from this that the proportion of species com- 
mon to the Black Hills and Eastern Nebraska and to the former 
locality and the Rocky Mountains is nearly the same when the 
numbers in all the lists are considered. From undetermined ma- 
terial on hand, however, it is very evident. that when thoroughly 
worked up, the lichen flora of the Black Hills will show a great 
many more species found also in the Rocky Mountains.* 
cerns % 
* Most of the specimens examined have come from the eastern side of the Hills) 
and we may expect more Rocky Mountain forms from the western side, for eee 
= later. 
