24 
IVoodsia Mexicana, Fee. — The Woodsia from Lower California 
mentioned in my Distribution Notes as likely to be W. obtusa proves 
to be this species instead. 
Mr. Orcutthas now re-collected it and supplied me with sufficient 
material to render its positive determination reasonably certain. 
My thanks are due to Mr. Orcutt for his kindness in this, and also 
for his efforts to procure for me other ferns, in -which I trust he 'will 
yet meet with equal success. 
r 
Notes on the Flora of Yellowstone Park. 
By Frank Tweedy, 
There is probably not an area of equal size in the United States 
which has as varied topographical features as the region of the Yel- 
lowstone Park, with its elevated plateaux and lofty mountain ranges, 
caiions, rivers and cataracts. Here also is the areat continental 
water-shed. The central portion is mainly a high, rolling, heavily 
timbered plateau varying from 7,500-8,500 feet above sea-level and 
bordered by mountain ranges on the west, north and east. It is to 
this interior region and to a few adjacent mountain summits that the 
following observations were limited. On travelling through the Park 
one is struck by the monotony of the forests as regards variety in 
species. The black pine {Pi'/ius contorta, Dougl., var. Murrayamh 
Engelm.) is the prevailing tree at low altitudes, forming at least 90 
per cent, of the forest area, mingled with a scanty growth of DougUs 
JDou 
of 
The latter are small and not to be compared with the noble tree 
the Pacific coast. We were surprised at the general absence of the 
yellow pine {Pinus ponderosa, Dougl), but probably the rainfall is 
too great for the healthy development of this species. Above 8,000 
feet, and even lower, dependent upon situation as regards temperature 
and moisture, occur the spruce {Picea Engelmannt, Engelm.) and the 
fir {Abies subalpina, Engelm.). The latter, much resembling the eastern 
balsam fir in growth and habit, clothes the cold, wet mountain slopes 
up to the timber-line, which here is nearly 1,000 feet. The black 
pine is not entirely confined to the plateau region, but often ascends 
to the timber-line along the drver ridges where it is frequently found 
with the western white pine \Piniis flexilis, James). A few red 
cedars are scattered over the sage-brush areas, and Jiiniperiis com- 
mu/iis, L., var. alpina, L., on alpine summits and more rarely around 
the geyser basins. A birch {Betula occidentalis) and the aspen {Popu- 
lus iremuhides, Michx.) are mostly confined to moist bottoms along 
streams. Early in August we occupied a camp in a small opening, 
half JDog, half meadow, on the eastern slope of the Gallatin Range. 
On either side were the fir-clad slopes of high mountain peaks. Scat- 
tered over the meadow were patches of low willows {Salix Geyeriana, 
Anders.) and birches {Betula glandulosa, Michx.) mingled with great 
quantities of Potenfilla fniticosa, L., the most characteristic shrub ol 
the mountain bogs. Blue gentians were missed in great profusion 
over the surface of the bog, Gentiana serrata. Gunner, everywhere, 
G. Forwoodii, Gray, and G. amarella, L., var. acuta, Hook., les 
