44 



are most reliable as zonal guides, he says: "Shrubs and trees, being com- 

 monly larger than herbaceous plants, reach higher into the air and penetrate 

 more deeply into the soil, thereby subjecting themselves to a wider range of con- 

 ditions than do these smaller plants. They also, by continuing throughout the 

 year exposed to successive, varying seasonal conditions, complete the full round 

 of their possibilities in environment. They therefore stand as the most complete 

 summation that can be attained of the natural light, heat, moisture, food, air and 

 mechanique of any area; in other words, a sure index of the natural agricultural 

 capacity of the soil upon which they grow. From a utilitarian point of view, too 

 much stress can scarcely be laid upon this fact. It has been the practice of agri- 

 culturists to gauge the capacity of soils, in regions new to the plow, by observa- 

 tions on rainfall, temperature, cloudiness, chemical composition of the soil, 

 drainage, and many other phenomena, or by the even more laborious process of 

 experimenting on evei'y farm with each kind of cultivated product ; ignoring the 

 fact that this determination can be greatly hastened, cheapened, and authenticated 

 by correlating the natural vegetation, especially that made up of the trees and 

 shrubs, with that of other regions, whose agricultural capacities are known."' 



A careful gathering of facts of the character indicated regarding our native 

 flora would not only give results of the highest practical value, but would also- 

 serve in a great measure to relieve chemists and agriculturists of irksome work, 

 the results of which at best could be of but local value. In this broader view 

 even systematic botany has opened before it a splendid opportunity, for I know" 

 to my sorrow how few facts of this kind are available. Here, also, it is evident 

 that data sufficiently extended can only be secured through intelligent co-opera- 

 tion of botanists throughout the State. No more attractive field offers; none in 

 which the prospect of valuable returns is more promising. 



A recent article in Nature, by M. T. Masters, abstracted in the Popular 

 Science Monthly for October, 1896, on "Plant Breeding," is also suggestive of 

 work of great practical value along botanical lines. Quoting briefly: "The 

 natural capacity for variation of the plant furnishes the basis on which the breeder 

 has to work, and this capacity varies greatly in degree in different plants, so that 

 some are more amenable and pliant than others. The trial grounds of our great 

 seedsmen furnish object lessons of this kind on a vast scale. The two processes 

 (selection and cross-breeding) are antagonistic. On the one hand, every care is 

 taken to preserve the breed and to neutralize variation as far as possible, so that 

 the seed may "come true;" on tlie other hand, when the variation does occur the- 

 observation of the grower marks the change, and he either rejects the plant,. 



^ Botany of the Death Valley Expedition , 18 



