Black Hills. 567 
Harney Mountains; Actaea spicata var. arguta, Aster sibiricus (= A. Richardsonii), Arnica alpina, 
Arenaria verna var. hirta, Dodecatheon pauciflorum, Epilobium paniculatum, Epilobium Drummondii, 
Helianthemum majus, Myosotis sylvatica, Pyrola rotundifolia var. bracteata, Leucocrinum montanum, 
eh (Wulfenia) rubra, Viola canina var. adunca (= V. adunca) while, as northeastern 
nts oceur Fragaria virginiana, Hypericum ee Lobelia spicata var. hirtella, Stachys 
aspera, Halenia (Tetragonanthus) deflexa, Viola blanda, Viola palustris”), — The damp atmosphere 
of the Harney range permits the following ferns to grow; Asplenium trichomanes, A. filix-foemina, 
A. septentrionale, Botrychium matricariaefolium (?),  Nenkfbälinn filix-mas and dryopteris, Cystopteris 
a Pteris aquilina, lee vulgare, Polypodium vulgare var. rotundatum, Selaginella 
‚ Woodsia oregana, W. pulina, 
The limestone table-land in the Black Hills is covered with Pinus pon- 
derosa var. scopulorum and Populus tremuloides and such shrubs as ARibes 
cereum, Shepherdia canadensis, Elaeagnus argentea, Ceanothus Fendleri, Salix 
Bebihnies S. discolor, Funiperus communis. The northern Hills have a woody 
flora in which the pine predominates. 
e following shrubs and lianes occur here in addition to those above mentioned: Cea- 
nothus ovatus, Potentilla fruticosa, Ampelopsis ee quinquefolia, Reg hirsuta var. 
ae Viburnum lentago, Vitis vulpina. Here in the canyons grow many eastern plants 
viz! ermum virginianum, E. deflexum var. americana, Lysimachia thyrsiflora, ehe rende 
var. Haie Lathyrus ochroleucus, Halenia deflexa, Viola scabriuscula, and the following weste 
species: Arnica alpina, A. cordifolia, Calochortus Gunnisoni, Claytonia ee: var. amplectens, 
Epilobium Drummondii, Frasera speciosa, Heuchera parvifolia, Hieracium Fendleri, Lesquerella 
spathulata, Lupinus Baar, Potentilla glandulosa, P. humifusa, en (Washingtonia) nuda, 
Mertensia sibirica, Mimulus luteus (M. Langsdorfi), Thalietrum occidentale, T. venulosum. 
3. Great Basin Region. 
Between the towering rim of the Sierra Nevada Mountains on the west, 
which prevents the moist winds of the Pacific Ocean from crossing, and a 
lofty eastern rim in part represented by the Wasatch range, that bars out the 
Gulf winds, lies a great area without any drainage outlet to either ocean, 
known as the Great Basin. The low south rim permits the hot dry south 
winds to sweep over the basin. Most of the valleys in this country are utter 
deserts. There is absolutely no water in them from one end of the year to 
the other. Small rivulets formed by melting snow run part way down the 
mountain slopes, but they sink out of sight before reaching the plain. The 
flora in such a region is, therefore, of a most pronounced arid type and desert 
shrubs and perennial herbs represent the chief components of the natural 
vegetation’?). 
A. Oregon District. 
The eastern portion of the states of Washington and Oregon is a great 
arid plain centering about the Columbia River and this plain owes its aridity 
ı) Rypperc, P. A.: Flora of the Black Hills of South Dakota. Contributions U.S. National 
Na 
Herbarium II, No, 8: 463—478; Bessev, C. E.: Ferns of the Black Hills. American turalist 
XXVI: 252; Wırrıams, T. A.: Notes on the Flora of western South Dakota do XXVI: 253. 
2) Cf. Liviscston, B. E.: The Relation of desert Plants to Soil-Moisture and Evaporation. 
Publ. 50 Carnegie Institution 1906. 
