181 



siderable and never develops more fully (Fig. 6 B, D, E; Fig. 7 -F; 

 Fig. 8); but in others, especially in those situated upon the 

 floral stem, the laminae may be fairly large and well-developed, 

 without any indications being present of the bulbils germinating 

 (Fig. 7 D). Intermediate forms between true scale-leaves and 

 true foliage-leaves occur abundantly (Fig. 8 Л, C). The bulbils 

 are small shoots which begin with two transversely placed leaves 

 (Fig. 6 D, see a; Fig. S Ä, B; Fig. 9 -4), then other leaves follow 

 spirally; but in the floral part of 

 the shoot these leaves develop new, 

 small, starch-containing shoots so 

 quickly, that in a leaf-axil may 

 occur a complex of shoots of se- 

 veral generations (Fig. 6 D), whose 

 reciprocal relation it is very diffi- 

 cult, if not impossible, to unravel. 



The bulbils upon the inflores- 

 cence are much smaller than are 

 those which occur upon the rhi- 

 zome. 



That the starch -containing 

 leaves of the bulbils serve as food 

 for the growing shoots, may be 

 taken for granted; those occurring 

 lowest on the rhizome shown in Fig. 6 E have been emptied, 

 while the uppermost are fresh and filled with starch; after the 

 scale-leaves, which have been emptied, follow foliûge-leaves, 

 and after them new scale-leaves. The small bulbils on the 

 floral shoot readily fall off and serve as organs of propagation. 

 LiNDMARK, who has given an exhaustive and accurate description 

 of the vegetative organs of S. cernua, has seen them and 

 figured them germinating. The same must be assumed regarding 

 those figured in Fig. 7 A, B. 



(A '"^phylloman" form, the scale-leaves of which had deve- 



Fig. 8. Saxifraga cernua. 



A, An imperfect foliage-leaf subtend- 

 ing a bulbil. B, A scale-leaf which 

 is also subtending a bulbil. C, A por- 

 tion of the basal part of a plant; 

 n, a scale leaf; Л, an imperfect foliage- 

 leaf; both are subtending buds ; L^ does 

 not subtend a bud. (E. W., 1886.) 



