190 



PLANT STUDIES 



drouth it is very com- 

 mon for plants to 

 diminish the exposed 

 surface in a very de- 

 cided way. In such 

 cases tliere is wliat 

 may be called a peri- 

 odic surface decrease. 

 For example, annual 

 plants remarkably 

 diminisli their ex- 

 posed surface at the 

 period of drouth by 

 being represented 

 only Ijy -well-pro- 

 tected seeds. The 

 whole exposed sur- 

 face of the plant, 

 root, stem, and leaves, 

 has disappeared, and 

 the seed preserves the 

 plant tlirough the 

 drouth. 



Little less remark- 

 able is the so-called 

 geophilous habit. In 

 this case the whole of 

 the i>lant surface ex- 

 posed to the air dis- 

 appears, and only 

 underground parts, 

 such as bulbs, tubers, 

 etc., persist (see Figs. 

 45, 4(;, GO, 07, OS, 

 00, 70, 75, 144, lOS, 

 WJ). At the re- 





Fiii. KIN. The bliKHlrodt. {Siiiiiiiii"<ir'<n. 

 Ilio siiliternincini roolslcirk .■-(■ihMiil; Ir, 

 Jiowcr iibovo the f>Lirf!ice.— Al'ttT Atkin, 



i\'('s and 



