60 Contributions from the Gray Herbarium 
IV. NEW OR OTHERWISE INTERESTING 
PLANTS FROM IDAHO 
By J. Francis MAcBrRIDE AND Epwin BLAKE PAYSON 
Durine the summer of 1916 we had the good fortune to be able 
to spend six weeks in botanical exploration in the south-central 
portion of Idaho. Practically the entire time was spent in Blaine 
and Custer Counties which represent probably the least known 
portion of the state, topographically as well as botanically, since 
portions of the searcely “ navigable’ lava fields which cover a 
large part of Blaine County are unknown and since Custer County 
has only one railroad point and that at Mackay near the south- 
eastern boundary. The region is additionally interesting to the 
botanist because of the great variation in the climatological con- 
ditions that exist in close proximity. Consequently in passing 
from the low and excessively dry lava fields to the foothills and 
mountain valleys and finally to the higher summits of the Sawtooth 
Range where the snow banks never completely melt away one 
encounters great diversity in environmental conditions which have 
resulted in the formation of many distinct types of vegetation 
ranging from essentially desert in the lava fields to alpine at the 
summits of the higher peaks. These higher summits in this part 
of the state are largely granitic in character but in the vicinity of 
Mackay they are, in part, composed of limestone. The latter 
formation was visited in 1911 by Nelson and Macbride and then, 
as this year when it was more carefully explored, yielded many 
things that were not discovered on the granitic peaks of the region. 
In spite of the fact that our time and our capacity for carrying 
presses was strictly limited we secured in the 1000 miles we 
travelled 1000 numbers, most of which consisted of twelve sheets. 
Unfortunately we were compelled because of lack of time and 
carrying space to take only the rarer and more important things 
and to confine duplication to the less usual or unrecognized species. 
Consequently the collection is not as representative of this region 
of the state as it might be. Nevertheless a critical study of the 
specimens has disclosed the fact that we secured many rare OF 
little known species, many new to the state and upwards of a 
dozen apparently undescribed. 
