52 



In a few cases the purpureus-\>\\& was not found alone, but also some adami- 

 buds of the nearest surrounding were changed into purpureus. So, this summer, 

 in my garden, of six quite independent, dormant, three years' buds at the summit of a 

 long-shoot of Cytisus adami, separated from each other by relatively short inter- 

 nodes of the longshoot, no less than four are changed into purpureus, and besides, 

 the two unchanged adamt-buds are placed between the higher and lower situated 

 purpureus branchlets. Accordingly the influence which caused the variation must 

 have been active simultaneously in four meristems, the distances between which, 

 at the time of the variation, must certainly have amounted to some tenth parts 

 of millimeters. 



Herewith I think to have made good the two statements expressed at the 

 beginning of this paper, and I only wish to add that already before, but at quite 

 another occasion (Ctcidiogfafse du Cynips colitis. Archives Neerlandaises, Ser 2, T. 2, 

 1897, pag. 436), I came to the opinion that variability, though habitually going 

 out from a single cell, is not necessarily always bound to it, but sometimes has a 

 cell-group as starting point, so that there can be question of uni- and pluri- 

 cellular variability. 



The relatively great number of bud-variants of adami, which I have examined, 

 consisted, as usually, only of pure laburnum- and pure/#r/wvr#.j-branches. Hybrids, in 

 which both factors occur, but one preponderant as compared to its part in adami. 

 seem never to be produced. Still I believe that in the cell layers of the bud-meristem, 

 which form the separation between adami and one of the variants, there must occur 

 transitory cells, which, could they be independently developed and cultivated into 

 new individuals, would produce such derivated hybrids. Perhaps the supplanting 

 of these transitory cells by the completely varied cells, may be compared to the 

 rarity (discussed in the preceding paper on the variants of microbes) of the sub- 

 variants as compared to the normal form and the main variants, by which it seems 

 possible to explain, on the one hand the existence of distinctly marked bounds 

 between the species, on the other hand, the not less marked bounds between the 

 different organs and tissues of the higher organisms. 



