70 REPORTS OF INVESTIGATIONS AND PROJECTS. 



The results of the first season warrant the extension and enlargement of 

 these cultures. 



The Lichens of the Desert Laboratory Domain. — In connection with Pro- 

 fessor Spalding's work on distribution, Prof. Bruce Fink, of Miami Univer- 

 sity, has made a critical analysis of the hchen flora of the vicinity of the 

 Desert Laboratory. Thirty-two species, representing 15 genera, a few of 

 which had not been previously known, were found. All were found to ex- 

 hibit structures suitable for endurance of low humidities, the action of wind, 

 and of insolation of high intensity. The presumptive evidence points to the 

 conclusion that these plants may absorb water vapor from the air. 



The Flora of the Tucson Region. — Prof. J. J. Thornber, of the University 

 of Arizona, has made an exhaustive determination of the seed-plants of the 

 region covered by Professor Spalding's investigations in plant distribution. 

 Among the more important generalizations made apparent by his work it is 

 to be cited that the flora of this portion of the desert consists of winter and 

 summer annual herbs to the extent of 43 per cent, of perennial herbs to the 

 extent of 22.6 per cent, the remaining 24.4 per cent being woody perennials. 

 Nearly half of the introduced species behave as winter annuals, and are from 

 the Mediterranean region. Sixty-eight families, represented by 269 genera 

 and 449 species, were formed, of which 22 genera were introduced by man. 



The Geology of Tiiinamoc Hill. — In connection with Professor Spalding's 

 studies in distribution, Prof. C. F. Tolman, of the University of Arizona, has 

 made an exact analysis of the geological features of the three low basaltic 

 hills on one of which the Desert Laboratory stands, and of the adjacent slopes 

 in the domain. Professor Tolman has given some consideration to the mod- 

 ifications of geological processes and deposits induced by aridity. In addi- 

 tion the petrography of the principal rock-formations has been made out. 

 The entire mass of information presented will be invaluable in all investiga- 

 tions dealing with habitats and distribution in this locality. 



Topographic and Bio-geographic Features of the Pinacate Region. — Tuc- 

 son, the site of the Desert Laboratory, is situated near the crest of a great 

 flattish ridge that extends from eastern Arizona to the Colorado River and 

 the Gulf of California. The naturalists of the iMexican Boundary Survey 

 traversed the southern slope of this ridge, but attention was chiefly given to 

 a narrow zone and no connected information as to the region existed. It was 

 deemed important that a traverse be made from the Desert Laboratory direct 

 to the shores of the Gulf of California, and note made of the principal facts 

 and conditions attendant upon the merging of this elevated desert with that 

 of the coastal area of the Pacific. To this end an expedition, including 

 among its members Dr. W. T. Hornaday, Director of the New York Zoologi- 

 cal Park, Hon. J. M. Phillips, Game Commissioner of Pennsylvania, Mr. G. 



