OS 



PLANT STTDIES 



certainly one of protection, und it has a further advantage 

 in the way of migration and vegetative propagation. As 

 the stem advances over the gronnd, roots strilve out of the 

 nodes into tlie soil. In tlii.s way fresh anchorage and new- 

 soil supplies are secured ; the old parts of the stem may 



Fig. 48. Two plants of a saxifrage, showing rosette habit, and also the numerous 

 runners sent out from tlie base, wliieh striice root at tip and produce new plants. 

 — After Kp:KM:it. 



die, but the newer portions have their soil <'oiinection and 

 continue to live. So effective is this haliit tor this kind of 

 propagation that plants with erect stems tifteii make use of 

 it, sending out from nea.r llic l)asc special jirostrati' hranches, 

 which advance ov<'i- tlie ground and form new ])lants. 

 A very ftuniliar illustration is furnished liy the straw- 

 berry j)lant, which sends out jioculiar naked "runners" 

 to strike root and form new plants, which then become 



