Rosaceæ. 49 



titious roots, while the upper bract subtends a new runner 

 of the same appearance as the parent-shoot. "The leaf- 

 'shoots he alternately to the right and left on the runner- 

 sympodium, from which it is evident that the branching is 

 as in a true scorpioid cyme" (Warming 1. c). From the 

 new adventive plants new runners may arise even during 

 the first summer (Wolf). 



As every runner may produce several new rosettes, when 

 circumstances are favourable, a parent-rosette of this plant 

 may give rise to a considerable number of new individuals all 

 around it. The runners die during autumn and by this means 

 the young shoots become independent. On the other hand, 

 in less favourable localities, where the runners are short, the 

 number of off-shoots is considerably reduced, and it is espe- 

 cially those shoots which are nearest to the parent-plant 

 which succeed in striking root and becoming independent. 

 It appears, especially in dry soil, to be a critical moment 

 for the young shoot when its roots emerge, because these 

 easily get dried up before they succeed in penetrating deep 

 enough into the soil. Further, it is only the inner shoots or 

 only the innermost one of the shoot-generations of the runners 

 which attain the flowering stage in unfavourable localities. 

 In cases where the flower is not immediately visible, an ex- 

 tremely small dead flower-bud may often be found hidden 

 among the bracts. 



Besides these creeping floral shoots the leaves of the 

 parent-rosette may also subtend new rosette-shoots which 

 may sooner or later become independent. 



As already mentioned the young adventive shoots are 

 provided with 1 — 2 strong adventitious roots. The latter 

 die in the course of the following summer while new ones 

 are developed. In older plants these one-year-old roots often 

 take the character of a food-storing root as shown in Fig. 19. 

 They are usually spindle- or club-shaped and may become 

 XXXVII. 4 



