CISTAOE^i 



93 



CISTACEiE 



Fig. 54. — Shoot of Helianthemmn 

 oslandicuvL. Slightly enlarged. 



Helianthemum 



The name is derived from ^Xto? and dvffefiov, sun- 

 flower. In some species the flowers bend over in wet, and 

 follow the sun in fine weather. 

 Vaucher, in his Histoire 

 Physiologique des Flantes, 

 writing on the Rock Roses 

 (Helianthemum), observes : 

 " J'indique dans ce genre deux 

 principaux objets de recherche. 

 Le premier est la raison pour 

 laquelle certaines especes ont 

 des stipules tandis que d'autres en sont privees." This 

 suggestion started me on the study of stipules. No one, 



so far as I know, had 

 attempted to answer 

 Vaucher's question, 

 which is one of consider- 

 able interest, and might 

 be asked with reference 

 to several other groups 

 besides the genus Heli- 

 anthemum. The results 

 of my observations have 

 been embodied in several 

 Memoirs which the Lin- 

 nean Society has done me 

 the honour to publish in 

 their Journal, and which 

 have been collected in 

 my book On Buds and 

 Stipules. H. vulgare 

 (Fig. 55) has stipules, 

 H. oelandicum (Fig. 54) has none. Now on examining 

 the various species of the genus I found that, where the 



Fig. 65.- 



-Shoot of J-Jelianthmium vulgare. 

 Slightly enlarged. 



