IOWA ACADEMY OF SCIENCES. 61 



abundance. Under the calcarous rocks, close to the riv- 

 er's edge, a few mesophytic willows, Salix loiigifoHa S. 

 amygdaloides and Pyriis sanibucifolia occur. TheBosa Fend- 

 leri, Amelanchier alnifolia, Bhus Canadensis Ya,Y trilobata ?iYe 

 also found in similar situations, but more commonly on the 

 drier soil above, especially true of the Amelancliier and 

 Bhus. 



The dry bench land above the flood plains receiving the 

 full rays of the sun show a temperature rising to 1 15° -120° 

 F. during the day. Only plants that can endure long 

 periods of drouth with a minimum transpiring surface are 

 able to grow. It is the region of Maniniilliaria, Eckino- 

 cacfiis and Opiintia, but these by no means make up the 

 bulk of the vegetation. 



The Cleome iuiegrifoUa, is evident everywhere along the 

 roadsides, and an occasional patch of Agropi/ron occideiifale, 

 with an abundant growth of Iva axillaris are characteristic 

 plant features of the lower belt, The vernal plants, no 

 doubt, are much more numerous, but their flowering period 

 is so short that they could not be recorded at this time of 

 the year. The upper area is cut by narrow and short can- 

 ons, well characterized by the abundance of Artemisia fri- 

 dentata, Bigelovia and the silky canescent Artemisia frigida 

 forming more or less flattened masses on the ground. The 

 spiny composite shrub Tetradymia Nuttallii with terete 

 branches, narrow, small leaves, covered with a hairry 

 tomentum, is well suited for this arid belt. Another spi- 

 nescent composite plant is associated with it the Artemisia 

 spinescens, occasionally also the Antriple.r longifolia, A. 

 canescens, and Sarcohatas vermiculatus. The introduced 

 Salsola Kali var tragus is common at the mouth of the can- 

 ons. With a few exceptions the plants are either fleshy or 

 hairy. 



THE UINTAH FOOTHILLS. 



I shall conflne my remarks in this paper to the flora of 

 Black's Fork, but the general features of the flora are 

 applicable to nearly all of the valleys on the north side of 

 the range. The general trend of Black's Fork, Smith's 



