OCTOBEK 18, 1901.] 



SCIENCE. 



601 



done before many of the genera are under- 

 stood and a great deal of territory must be 

 explored before the species are approxi- 

 mately known. Following this work, the 

 problems of geographical distribution can be 

 solved and life zones satisfactorily mapped 

 out. 



14. ' The Xerophytic Vegetation of the 

 Uintah Mountains': L. H. Pammel. 



In the Uintah range occur types of plants 

 from the arid regions of the Southwest, 

 boreal types in the mountains farther north- 

 ward, and many forms from the main 

 Eocky Mountain flora. The largest xero- 

 phytic areas occur in the Colorado and Green 

 Eiver basins. The xerophytic vegetation 

 of the Uintah range varies with the differ- 

 ent physiographic conditions and geologic 

 formations. One naturally expects to find 

 a very different flora in passing through 

 the Green River and lower basins up to 

 the higher peaks such as Gilbert, La Motte 

 and Wilson ; however, at an altitude of 

 9,200 feet the valleys and park-like open- 

 ings have many xerophytic plants common 

 to the lower basins of the streams. The 

 succession of plant formation in this region 

 is fairly well marked ; it is not difficult, 

 therefore, to trace a succession of plant 

 life on the flood plains since the quatern- 

 ary. The foothill and mountain floras 

 change successively from hydrophytic to 

 mesophytic, then to xerophytic and finally 

 culminate in the mesophytic of the foot- 

 hills with hydrophytic basins. In the 

 Green River basin and the tributaries 

 of the immediate vicinity of this basin 

 the xerophytic plants are much more pro- 

 nounced than in the foothills. In the 

 broad flood plains of Green River there 

 occur such plants as Dlsticlilis spicata, the 

 widely distributed Hordeum jubatum, and 

 the western S. ccespitosum. The habit of 

 growth and the manner of reproduction of 

 Distichlis make it well adapted to the con- 

 ditions prevailing in that arid region. Two 



Capparidaceous plants, Cleome integrifoUa 

 and G. lutea, are common. A somewhat 

 similar yellow-flowered crucifer, Stanleya 

 pinnatijida, is scattered through the dry low- 

 lands. Naturally one expects to find many 

 chenopodiaceous plants. Their succulent 

 leaves enable them to adapt themselves to 

 these dry regions. Sarcobatus vermiculafus, 

 Chenopodium fremontii, C. rubrmn, Eurotia 

 lanata and Suceda depressa are common 

 plants of the dry basins. Artemisia triden- 

 tata with its accompanying Eriogonum ovali- 

 folium and E. umbellatum are common at 

 higher altitudes along Black's Fork. The 

 terrace formation is especially well marked 

 from the mouth of Black's Fork up to 8,500 

 feet. In the lower region there are small 

 groves of Junijoerus occidentalis var. mono- 

 sperma, frequently accompanied by Picea 

 pungens, Juniperus communis and Ardosta- 

 phylos. At an altitude of 7,500 feet three- 

 well-defined flood plains are recognizable. 

 The present flood plain contains mesophytic 

 groves, the second flood plain is dotted with 

 small patches of trees and sage brush, the 

 third flood plain contains no trees. Arte- 

 misia tridenfata is the most characteristic 

 plant. Symphoricarpos, Lupinus and Sti'pa 

 also occur. From the third flood plain 

 there is an abrupt rise of from three to five 

 hundred feet. The sides are lined with 

 SyynpJioricarpos, Primus, and some sage brush. 

 The top of the benches contains almost no 

 trees except farther up, but sage brush, 

 Eurotia lanata, Stipa, Castilleia, Orthocarpus 

 and Eriogonum are characteristic plants. 



15. '■ Some Aspects of the Wyoming 

 Desert Flora ' : Aven Nelson, 



South central Wyoming contains an ex- 

 tensive area known as the Red Desert. 

 This has a considerable flora, the most ob- 

 vious members of which belong in the 

 genera Artemisia, Atriplex, Chrysothamnus, 

 Tetradymia, Sareohatus, and Agropyron. Be- 

 sides this there is a very considerable 

 fugacious vegetation. This desert flora, 



