^02 



PLANT STUDIES 



tance in xerophytic conditions. In 

 the cactus jilants the peculiar stems 

 have become great reservoirs of 

 moisture. The globular body may 

 be taken to represent the most com- 

 2)lete answer to this general problem, 

 as it is the form of body by which 

 the least amount of surface may be 

 exjiosed and the greatest amount of 

 water storage secured. In the ease 

 of fleshy leaves and fleshy bodies it 

 has long ])een noticed that they not 

 only contain water, Init also have a 

 great power of re- 



FlG. ]Sl). A fra;^nn'nt of bar- 

 licrrv, stiDwin^ tlu' ttioriis. 

 — Aft'T Kehner. 



Fir.. 1H1. TwiKof com- 

 Diou locust, Bho\\iiig 

 the thorns.— After 

 Kerneh. 



ttiining it. Plant 



collectors have found great difficulty in 

 drying these fleshy forms, some of which 

 seem to be tible to retain their moistui'e in- 

 definitely, even in the driest coiulitious. 

 144. Xerophytic structure. — The adap- 

 tatiiins given above are generally foun<l 

 in ])lants growing in drouth cnnditions, 

 and thev all implv tin ettVirt to diminish 

 trauspirtition. It must not be siippiiscd, 

 however, thtit oidv jihints living in 

 drouth conditions show these adaptti- 

 tions. Such ;ida})tations result in what 

 is kiK.iwn as the xerophvtic structure, 

 and such ;i structure mav appear even 

 in plants growing in hyilroi>]iyte condi- 

 tions. For example, the bulrush grows 

 in shallow water, and is ;i })rotninent 

 member of one of the hvdrophvie soiae- 

 ties (see ^l'o2) ; ;ind yet it has a. remark- 

 ably xerophytic structure. This is prob- 

 ably due to the fact that although it 



