90 Rhodora [May 
West of the Falkland Islands it is found on Tierra del Fuego, whence 
it follows slightly northward on the high Andes as P. mohrioides, 
var. plicatum (Poeppig) Christensen! or P. andinum Phil., which 
differs from the Falkland plant only in its dwarf size (growing in 
exposed alpine habitats) and in the paler and thinner scales of the 
stipe. Skottsberg got a form of P. mohrioides on South Georgia, 
800 miles (1290 km.) southeast of the Falklands; Moseley, during the 
voyage of the Challenger, collected an extreme form on Marion 
Island, 1200 miles (1930 km.) southeast of the Cape of Good Hope 
and more than 3000 miles (4800 km.) northeast of South Georgia; 
and the next year De l'Isle discovered the species on Amsterdam 
Island, more than 2000 miles (3200 km.) east of Marion Island. 
Northward, in the Andes, it occurs as P. mohrioides, var. elegans 
(Remy) Christensen? or P. elegans Remy, an extreme with longer 
and more divided pinnae. 
In North America two members of this alliance are recognized: 
P. Lemmoni Underwood and P. scopulinum (D. C. Eaton) Maxon, 
both confined to arid regions of the Sierra Nevada-Cascade axis, 
with the exception of four isolated stations for the latter, one each 
in the Teton Mts. of Idaho, the Mission Mts. of Montana, the Wasatch 
Mts. of Utah and the Shickshock Mts. of Gaspé Co., Quebec. So 
close are these North American plants to those of. the southern 
Andes and the Falklands that the late D. C. Eaton, after trying to 
find specific differences, described and illustrated? as typical P. 
mohrioides (or Aspidium mohrioides) the Californian P. Lemmoni 
and at the same time, in describing his Aspidium aculeatum, var. 
scopulinum, he surmised that it belonged with P. mohrioides, saying: 
“T have some doubt about the plant here named var. scopulinum, as 
it differs more from all the rest than any of them do from each other. 
It has a little the habit of A. mohrioides, but, though the specimens 
I have seen are old, they still keep in a degree the aculeate points of 
the present species."* And again he wrote that his var. scopulinum 
was “almost as much like A. mohrioides as it is like A. aculeatum, but 
as it has the lobes of the pinnae somewhat aculeate it is better to 
leave it with the latter species." ? As already stated, Eaton had 
tried to find specific characters for P. Lemmoni but was unable to do 
! Christensen, Arkiv fór Bot. x. No. 2: 17 (1910). 
2 Christensen, 1. c. (1910). 
3 Eaton, Ferns of N. A. ii. 251, t. Ixxx. figs. 4-9 (1880). 
4 Eaton, l. c. 127, 128. 
t Eaton, | c. 254. 
