STEMS 



731 



mountains developed short and stout stems, the whole aerial system 



assuming a bushy and compact habit. The leaves and flower stalks, 



as well as the stems, 



underwent reduction 



(figs. 1051,1052,869, 



870). Hence alpine 



conditions are 



thought to account 



for the prevalent 



habits of alpine 



plants. 



Krummholz. — 

 The mountain pine 

 of Europe (Pinus 

 montana) in the 

 Alps is a gnarled 

 and sprawling, much- 

 branched shrub, but 

 when grown in the 

 lowlands it is a tree 

 muchlikeotherpines. 

 German botanists 

 use their common 

 name for this plant, 

 Krummholz (gnarled 

 wood), as a general 

 term for the scrubby 

 growth of woody 

 plants above the tim- 

 ber on mountains, 

 and for lack of a suit- 

 able English term, 

 the word may be em- 

 ployed here. On 

 most mountains the 

 "timber line" trees 

 pass gradually up- 

 ward into a scraggy 

 Krummholz; good 



Figs. 1051, 1052. — Leaf and stem variation in Heli- 

 anthemum vidgare: 1051, an individual grown in a lowland 

 garden, showing elongated stems and relatively large leaves; 

 1052, an individual grown in an alpine garden from a part 

 of the same plant from which 1051 was taken; note the 

 numerous dwarfed branches with their much smaller leaves 

 and but slightly smaller flowers; b, bracts; x, calyx; c, 

 corolla ; both figures equally reduced. — After Bonnier. 



