205 



sometimes, however, the leaf-pairs do not cross each other 

 exactly at right angles (Fig. 24 G). The stems of this form 

 may form a low carpet of greater or lesser extent. 



The form with a pul vin a te habit, has usually only a primary 

 root; it gives off lateral branches, more or less erect, forming 

 dense, semi-globular cushions which, according to Andersson 

 and Hesselman, may attain a diameter of 20 — 30 cm. and a 

 height of 10 cm. Prostrate branches appear sometimes to be 

 quite absent. I have gathered similar specimens, cushion-like 

 in habit and richly-flowering, in Finmark; and in the "Riks- 

 museum" in Stockliolm, there is a specimen in spirit (in a 

 glass measuring 5 cm. in width) gathered by Nathorst, which, 

 is as large as a clenched fist, and has about 120 flowers. 



Fig. 24. Saxifraga oj^positifolia. 

 A, Flowering shoot (West Greenland; July 12, 1884; slightly above nat. size). B, A shoot 

 ^West Greenland; May 18; a little above nat. size) with a terminal flower; at x the fresh 

 green leaves begin. C, Branch from Norway (Finmark); July 7. D, Shows a lateral shoot 

 which begins with an elongated internode. E, Plant from West Greenland, reduced 

 (July 17); leaves very close-set. F, Q. Diagrams to show the position of the leaves on 

 the erect short shoots. H, J. Branches of the same plant (Norway; Aug.); internodes 

 fairly elongated; a, limit of the j'ear's-shoot, slightly reduced. (Drawn by E. W.) 



The shoots branch irregularly; there is no principal bud. The 

 erect shoots with short internodes rarely branch before flowering; 

 the prostrate shoots give off branches which are also prostrate. 

 Between loose moss the internodes of the shoots may become 

 greatly elongated. 



The leaves are foliage-leaves; scale-leaves do not occur. 



