NATUIIAT> AREAS AND REGIONS 



155 



Above the hemlock-white tir tyi)e and 

 below cold timber-line is the suh-alpine 

 type of no commercial value, the species 

 consisting of mountain hemlock {Tsugn 

 Mertensiana), alpine fir {Abies lasio- 

 carpa), lodgepole pine, and with some 

 spruce and western hemlock. As a 

 rule a considerable portion of this type is 

 treeless and tundra in character, the 

 soil being wet and covered with a thick 

 growth of moss. 



B. TEMPERATE SEMI-DESERT BROKEN AND 



BUSH COVERED GRASSLAND (dRY- 



belt) (J. D.) 



1. General 



The semi-desert regions of British 

 Columbia are characterized by the 

 scarcity or absence of trees and the pre- 

 dominance of sagebrush {Artemisia 

 tridentala and A.frigida) ; rayless golden 

 rod {Bigelouia dracunculoides) ; balsam 

 root {Balsamorhiza sagittata) ; and other 

 white-pubescent xerophytic plants. 

 (For a discussion of grasses, etc., see 

 page 156.) 



There are three main drybelt regions: 

 (1) the Columbia-Kootenay semi-arid 

 area, in the valley between the Rocky 

 Mountains and the Purcell Range, com- 

 prising the Windermere Valley and the 

 region to the south; (2j the Okanagan- 

 Similkameen area; between the Gold 

 Range and the Cascade or Coast Range; 

 (3) The Eraser area including the 

 Thompson Valley, extending north 

 through the Interior plateau to latitude 

 53°. In each of these areas may be 

 found noteworthy variations in the 

 flora which may be summarized by se- 

 lecting two characteristic drybelt genera 

 Purshia tridentala (locally known as 

 "Greasewood"), and Opunlia polya- 

 cantha, (Cactus) and noting their 

 distribution: 



As Purshia is one of the characteristic 

 members of the Sonoran life zone, it is 

 interesting to note its presence in the 

 southern valleys which ultimately drain 

 into the Columbia River. 



Taken as a whole, the semi-desert 

 flora is found onlj* in the valleys and 

 adjacent benches; although Artemisia 

 Iridentata is most frequently given as 

 the characteristic sage brush, Artemisia 

 frigida is the species most widely dis- 

 tributed in the drybelt regions of this 

 Province. Where Artemisia tridentala 

 is found, the Cactus {Opunlia polya- 

 cantha var. borealis) is usually very 

 prolific. Associated with these may 

 1)6 found large clumps of milkweed 

 (Asclepias speciosa), and stickweed 

 (Mentzelia laevicaulis) . 



The flora of such a region in spring and 

 early summer differs greatly from that 

 found later in the year. For a short 

 season after the melting of the winter's 

 snow, when the soil is warm and moist, 

 the desert region is ablaze with many 

 annuals and perennials which send up 

 their flowers and hurry through with 

 the production and dispersal of seeds 

 before the soil becomes hot and dry. 

 Spring flowers include the yellow fritil- 

 lary {Fritillaria pudica) ; Mariposa lily 

 {Calochortus macrocarpus) ; Menzies Pha- 

 celia {Phacelia Menziesii); balsam root 

 {Balsamorhiza sagittata); clematis (C. 

 ligusticifolia) ; bitter-root {Lewisia re- 

 diviva). The fritillary, Mariposa lily, 

 balsam-root, and bitter-root grow in 

 such abundance that the bulbs or roots 

 are dug and used as food by the Indians 

 of these regions. 



In the numerous gulches caused by 

 erosion, may be found thickets of June- 

 berry {Amelanchier alnifolia), moun- 

 tain maple {Acer glabrum), and sumach 

 (Rhus glabra). 



Mammals, birds, and reptiles {E.A.P.). 

 Mammals of the sagebrush area include 

 a pocket gopher (Thomomys fuscus), 

 Lord's pocket mouse {Perognathus lordi), 

 and western white-tailed jackrabbit 

 {Lepus toionsendii townsendii). These 

 enter British Columbia only in this 

 area. 



Birds found almost exclusively in this 



