January 31, 1910 5 



marked classes, are selected for minute investigation; and an 



important section is devoted to the dispersal, and to the topo- 

 graphical advance or retrocession of species. In this connection 

 interesting remarks are included touching the agency of animals 

 in aiding, or in restricting, the multiplication of plants. Soil 

 conditions, as to moisture, temperature and aeration, as well as 

 to mechanical and chemical constitution, are shown to be the 

 determining factors in the distribution of some species, while 

 others are mainly influenced by aspect, which is but another 

 name for temperature and evaporation. The conclusion reached 

 is, that "desert plants are governed by the same general laws in 

 their relation to environmental conditions as are those of other 

 regions ," but acting under different limitations. 



Besides Dr. Spalding's own work there are included in the 

 paper contributions from several other naturalists. Dr. Bruce 

 Fink discusses the lichens of the domain, and Dr. W. A. Can- 

 non contributes a study of the root system of the sahuaro. The 

 geology of the area is described by Professor Talman, and the 

 soils by Dr. B. E. Livingston. Professor Thornber reports on 

 the vegetative groups, and lists the plants of each distinctive 

 subarea, dividing them with reference to form and duration. 

 The origin of desert floras is ably treated by Dr. MacDougal. 

 In fine, Dr. Spalding may be said to have given us the most im- 

 portant contribution yet made to the knowledge of the plant life 

 of the arid west. — S. B. Parish. 



THE FIRST SPRING FLOWER 



By A. A. Hki.i.kr 



I With cover illustration) 



By studying the records of plant collections, one may dis- 

 cover much concerning the advances made in the study of bot- 

 any, and the progress of knowledge in general. 



Only a few years ago it was a common practice to record 

 the name of the state where the plant was collected, and some- 

 times the year was added and sometimes it was not. A few ex- 

 amples are: "Oregon: coll. Klihu Hall, ami. 1S71;" "Southern 



