7 6 SCIENCE PROGRESS 



not shaded and therefore drawn, the height is a general index 

 of luxuriance, yearly observations on the average height of 

 these plants from selected localities were made and compared 

 with the rainfall. 



In the majority of cases the relationship between the 

 figures obtained did not warrant any definite conclusion. In 

 some instances, however, there was a definite relationship, 

 wherefore a more detailed examination was made. 



The following are the figures for the locality C. 17 : 



Number of plants on the station in 1907 no 



Average length 68 mm. 



Average diameter 3 mm. 



Total surface 700 sq. cm. 



Loss of water per hour per 100 sq. cm. of surface 1 . . . = "137 gm. 

 Loss of water in 3,960 hours 2 per 700 sq. cm. of surface . = 3797*64 gm. 

 Amount of rain which fell on station during the period . = 128821 gm. 



Assuming that all this rain was available for the use of 

 the plants, the amount was sufficient for the needs of, roughly, 

 35 times as many plants of Salicornia as occurred on the station. 



If, however, station C. 8 and 9 be taken, the population in 

 the same year was 5,970 plants, i.e. more than 50 times as 

 many as on C. 1 7, which means that the amount of rain was less 

 than the amount of water lost in transpiration. 



Although these figures are approximations, the considera- 

 tion of them points to the probability that sources of water 

 other than rain obtain and possibly means of absorption other 

 than the roots. It is well known that the leaves of ordinary 

 plants can absorb water ; it is the obvious thing, then, to 

 ascertain whether the aerial parts of halophytes such as Sali- 

 cornia can do likewise, and thus take advantage of rain, dew, 

 or even the sea-water at the times of high tide. 



Shoots of Salicornia annua 3 were removed and the cut 

 ends sealed with wax ; they were then dipped into water, 

 their surfaces dried as well as possible, and weighed. The 

 shoots were allowed to wither for some time, during which 

 period they were occasionally weighed after being dipped into 

 water and dried as before. At the end of the withering the 

 shoots were immersed in water for a varying number of hours 

 and were again weighed after being superficially dried. 



1 Based on Delf's observations, Ann. Bot. 25, 485, 191 1. 



2 From April i to September 12. 



3 Delf, loc. cit. 



