1917] Butters,— Studies in Ferns — Botrychium 213 
lobe of the ultimate segment of the fertile frond. When the spor- 
angium has opened, an inside view has something the appearance of 
the inside of a straw hat, the shallow crown of which is formed by the 
wide lower part of the sporangium. The herbaceous base then ap- 
pears as a dark spot in the middle of the open sporangium, correspond- 
ing in its position to a lining in the top of the crown of the hat. The 
sporangia in this variety are as small as in typical Botrychium vir- 
ginianum, rarely over 0.7 mm. long and their walls consist of irregular 
cells with flexuous walls, as in the typical form. 
A single specimen of Botrychium virginianum var. europaeum from 
the eastern states, that from Randolph, N. H., previously noted as 
peculiar, shows a somewhat similar broadening of the base of the 
sporangium, though to a smaller degree. In the size and the micro- 
scopical structure of the sporangia it corresponds with the var. 
europaeum. Otherwise the specimens displaying the peculiarity here 
discussed are all western, and I am calling the variety 
BoTrRYCHIUM VIRGINIANUM (L.) Sw. var. occidentale, var. nov., 
varietati europaeo similis sed sporangiis 0.5-0.7 mm. longis, basin 
versus latioribus herbaceis late apertis. 
The following specimens are in the Gray Herbarium: 
Montana: Swan Lake, near Flat Head Lake, August 25, 1908, 
Mrs. Joseph Clemens (in part). 
Ipamo: deep woods near the south end of Lake Pend d’Oreille, 
July 28, 1892, Sandberg, McDougal and Heller no. 762 (type). 
OrEGON: Hood River, April 1882, Mrs. P. G. Barrett. 
CALIFORNIA: without locality, 1873, “ Miller.” 
In Mexico there are two Botrychia belonging to the group now under 
discussion. One of these occurs also in Central America and the 
West Indies, and possibly also in the Andes. The other, apparently 
confined to Mexico, has usually been considered as Botrychium vir- 
ginianum, but it differs so much from the typical form of that species 
in the form and cutting of the sterile frond, that it should be distin- 
guished as a variety, BorRYCHIUM VIRGINIANUM (L.) Sw. var. meri- 
dionale, var. nov., fronde sterili haud ternata, pinnis basalibus eas 
secundas parum superantibus, pinnulis ovatis ad basin cordatis vel 
truncatis vel brevissime cuneatis pinnatifidis, segmentis ordinis tertii 
approximatis obovatis seu spathulatis obtusissimis crenulato-serratis, 
fronde fertili atque sporangiis iisdem Botrychii virginiani typici 
similibus. 
This plant is evidently closely allied to true Botrychium virginianum 
with which it agrees entirely in the character of the fertile spike and 
the details of the sporangia except that the valves of the latter are 
usually somewhat less recurved in dehiscence. It differs, however, 
in both the form and the cutting of the sterile frond. The basal 
pinnae are only slightly longer and wider than the second pair, so that 
the frond is distinctly pinnate rather than ternate. The pinnules 
are wider and shorter than in the typical form and are truncate or 
