204 



In some plants the stems are prostrate, have more or less 

 elongated internodes, and attain a length of from 10 to 30 cm. 

 (Fig. 23; Fig, 24 Д' — J); many lie quite freely upon the ground, 

 but some are attached to the soil by adventitious roots. The 

 primary root remains alive for several years, ordinarily, no 

 doubt during the Avhole life of the plant, but sometimes the 

 adventitious roots become strong and the plant may multiply 



Fig. 23. Saxifraga oppositifolia. 

 (From the East of Iceland; Dec, 31, 1893.) 

 A prostrate shoot with two erect floral shoots bearing the dehisced capsules of the pre- 

 vious year and also several younger floral shoots, the fully-developed flowers of which 

 are enclosed between the fresh green leaves (Helgi Jonsson, 1895; drawn by С Thornam). 



by vegetative propagation. This, however, appears to occur 

 comparatively rarely. In forma reptans (Andersson and Hessel- 

 man) the adventitious roots appear to be more abundant than 

 is usual. 



The prostrate shoots give off erect floral shoots the leaves 

 of which are usually so close-set, and the internodes so short, 

 that they become square (Fig. 24 5, £■; Fig. 25 Л). The leaves 

 are generally opposite and decussate (Fig. 25^, Fig. 24 i''), 



