On the development of Buds and Bud-variations 



in Cytisus adami. 



Proceedings of the Section of Sciences, Kon. Akademie van Wetenschappen, Amster- 

 dam, Vol. Ill, 1900, biz. 365371- - Verscheen onder den titel 0ver het ontstaan van 

 knoppen en knopvariaties bij Cytisus adami in Verslagen Kon. Akademie van Weten- 

 schappen, Wis-en Natuurk. Afd., Amsterdam, Deel IX, 1900, biz. 336 342, en onder 

 den titel Ueber die Entstehung von Knospen und Knospenvarianten bei Cytisus adami* 

 in Botanische Zeitung, Leipzig, 59. Jahrgang, 2. Abteilung, 1901, S. 113-118. 



Cytisns adami is a hybrid between the common laburnum, Cytisus laburnum, 

 and a little shrub from Styria, Cytisus purpureus, with purple flowers. Now 

 and then are found on Cytisus adami buds of both species as bud-variants*). The 

 experience that these buds appear in particular on older parts, and have, probably 

 without exception, passed one or more years in dormant condition before budding 

 and changing into the primitive forms 2 ), induced me to cut down all the bran- 

 ches and the main stem of four specimens of C. adami in order in this way to 

 excite the development of the very old buds which were, since years, in dormant 

 condition on the old trunk. My expectation, that by these means I should obtain 

 a great number of bud-variants, proved right: in few years I saw, together with 

 earlier observations, appear more than a hundred buds of laburnum and about 

 twenty of purpureus. I was thereby enabled to establish a few paticularities about 

 buds and bud-variations which follow here: 



1. The ordinary axillary buds of Cytisus adami spring not from single cells 

 but from cell-groups. They grow on by means of a pluricellular meristem, and 

 not by means of one terminal cell. The latter fact was long known already and 

 is here anew confirmed. 



2. The bud-variants, also, originate from cell-groups and not from single 

 cells, so that the cause which is active here in producing variability, must extend 

 over many cells at a time. 



That this cause is in some or other way related to unfavorable conditions 

 of nutrition cannot be doubted. 



Of course the possibility is not excluded that for C. adami buds and bud- 



') The word variant is here used in a sense somewhat different from that in the 

 preceding paper on the variants of microbes, component might perhaps be more 

 precise in this case. But I keep to the usage, as the meaning is clear. 



2 ) This does not hold good for the flowers, which have no dormant period but 

 constantly develop in the 2<1 year, and of which the different parts are still more subject 

 to return to the components than the vegetative buds. But the flower may, even 

 unreckoned the process of fertilisation, be called the organ of variability. 



