66 carnegip: institution of Washington. 



hitherto unknown were found below the level of high-water mark and 

 described by Mr. Parish. It is not easy to point out their origin, but 

 their occurrence within the limits of the Sink only suggests that 

 the conditions prevalent in this restricted area may have had some 

 connection with the matter. 



It has been pointed out by Mr. Parish that within the limits of the 

 Sink there also occur Astragalus li7natus,A. aridus, Crijpta7ithe costata, 

 Calandrina amhigua, and Sphceralcea orcuitii, which are endemic and 

 do not extend beyond the high-beach level, with the exception of 

 Calandrina, which has evidently spread over toward the Colorado 

 River. Seven species in all have originated within the Sink and their 

 habitats still lie mainly within its area. Others may have had their 

 origin here and have been disseminated beyond the basin. 



VARIOUS INVESTIGATIONS. 



Analysis of the Effect of Climatic Complexes, by D. T. MacDoiigal 

 and Collaborators. 



After trials of a large number of species, less than a score have 

 been selected which wdll live in the climates presented by the moun- 

 tain plantations in Arizona, in the desert at Tucson, and near the 

 sea-shore at Carmel, California. The experimentation includes atten- 

 tion to two principal features. First, the morphogenesis of the 

 plants under the influence of the differing environic conditions pre- 

 sented is followed, from which it is seen that not only does the char- 

 acter of the seasonal or life cycle vary under different conditions, and 

 the vegetative parts of the plant show distinctive features under the 

 three sets of conditions, but some of these effects are carried over 

 from one generation to another. The reactions of any given species 

 at the Coastal Laboratory at Carmel will therefore vary according 

 to the previous experiences of the individuals or their ancestors. 

 The correlation of these differences with the factors in the climate 

 presents a much more difficult task. It is possible to measure the 

 evaporative capacity of the air as an expression of the combined 

 or resultant action of the wind, relative humidity, insolation, and 

 temperature. Methods are being developed for estimating the inso- 

 lation effect alone, and the integration of the temperature exposure 

 is one of the most pressing necessities of modern plant physiolog.y. 



Averages of maxima, minima, or statements of the range between 

 winter and summer, have only a remote empirical relation to plant 

 activity, which may be exactly conceived only in terms of velocity 

 of chemical reactions and physical change, upon which all vegetative 

 processes depend. Nothing yet brought out is superior in usefulness 

 to the empirical method of integrating the thermographic record 

 proposed by the author in 1901, but this matter has been taken up 

 anew with some faint hope of placing it upon a rational basis. 



