10 BOTANY OF THE DEATH VALLEY EXPEDITION. 



On the 25th and 2<ith Mr. Bailey and 1 made an excursion about 10 

 miles northward from Whitney Meadows toward Mount Whitney. 



August 28 I left Whitney Meadows, retracing our previous route, 

 reaching Visalia September 1. The botanical held work of the expedi- 

 tion being now ended, I proceeded to San Francisco and from jthat 

 point to Washington. 



PRINCIPLES OF PLANT DISTRIBUTION. 



DEFINITION OF TERMS. 



In a discussion of the principles of plant distribution it is necessary 

 that each term technically employed shall have a well defined and uni- 

 form meaning. Among those words which have been used by various 

 writers with great looseness, there are four which are of especial im- 

 portance to us, range, locality, station, and habitat, One lias merely to 

 refer to our common botanical textbooks and dictionaries to find the 

 lack of clearness in the definitions of these terms, while an attempt to 

 use the words as defined impresses one with the necessity of reviewing 

 their meaning. 



Of these words the one which has historic precedence is habitat. It 

 has been used at various times to express the different meanings 

 which are now conveyed by all four words, and from this fact an un- 

 fortunate confusion has arisen. Another circumstance that has con- 

 tributed to the cloudy understanding of these terms is that a technical 

 meaning, not in accord with its popular use, has been ascribed to one 

 of them. The word referred to is station. This term is sometimes 

 employed to express the kind of place in which a plant occurs; but its 

 historic use in the language is to indicate position merely. 



The meanings that should logically be attached to these words are 

 as follows: 



lianye — the region over which a type spontaneously grows. 



Locality — the approximate geographic position of an individual speci- 

 men. 



Station — the spot upon which a specimen has been collected or 

 observed. 



Habitat — the character of the place in which a type occurs. 



In these definitions the word type is a general expression lor which 

 in particular cases variety, species, genus, or the name of any group 

 may be substituted. 



To illustrate the use of these terms, let us take as an example the 

 species Juncus cooperi and the particular specimens of it collected 

 under No. 204 of this expedition (page 237). The data may be tabu- 

 lated as follows: 



Range, in the Lower Sonoran zone, from Vegas Wash, Nevada, west- 

 ward in California through the Amargosa Valley, Death Valley, and 

 Pauamint Valley, and again at Borrego Springs in the Colorado Desert. 



1 



