Fig. 204. Two plants of a rock-rose {Heliaiithemwn), showing the effect of low 

 ground and alpine conditions. The low-ground plant («) shows an open habit, 

 and elongated stems with comparatively targe and well-separated leaver. The 

 same plant in alpine conditions is drawn to the same scale in ft, and magnified in 

 c, the very short and compact habit being in striking contrast with that of the low- 

 ground form.— After Bonnier. 



