Fig. 196. Two plants of a rock-rose (Ilelianthenivm), showing the effect of low 

 groand and alpine conditions. The low-ground plant {a) shows an open habit, 

 and elongated stems with comparatively large and well-separatfid leaves. The 

 same plant in alpine conditions is drawn to the same scale in 6, and magnified in 

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

 ground form. — After Bonniek. 



