62 



publication of P. NIELSON in 1887, but which contains also some very 

 original remarks and observations, we may call an extensive publica- 

 tion in the "Nederlandsch Kruidkundig Archief" of 1882, entitled 

 "Over het ontstaan van knoppen en wortels uit bladen" (On the 

 development of buds and roots from leaves) BEIJERINCK'S first purely 

 morphological publication >). 



This treatise forms the first of a series of studies dealing with the 

 genesis of adventitious organs in the whole vegetable kingdom, in un- 

 derground organs as well as in those above ground. This explains 

 why the publication is not restricted to the formation of buds and 

 roots from leaves, as the title would suggest. In the introduction, 

 adventitious organs are discussed in general, and even a schema- 

 tical figure is explained wherein the possible arrangements of such 

 organs on various parts of a plant is represented. It is evident that 

 BEIJERINCK was strongly influenced here by the important study of 

 H. VOCHTING, "Ueber Organbildung im Pflanzenreich", which ap- 

 peared in 1878 -), but the works of TH. A. KNIGHT, A. BRAUN, A. DE 

 CANDOLLE, CH. DARWIN, J. SACHS and A. DE BARY also appear to 

 have influenced his modes of thought. Below we shall return more 

 specifically to the results of this 1 882 study, but we shall first discuss 

 BEIJERINCK'S observations in the related field of regeneration. 



A treatise "Over regeneratie-verschijnselen aan gespleten vegeta- 

 tiepunten van Stengels en over bekervorming" (On regeneration 

 phenomena of split vegetation-points of stems and on the formation 

 of ascidia), which appeared in 1883, has as its starting point observa- 

 tions which BEIJERINCK made while at the Government Agricultural 

 College at Wageningen on stems of different varieties of Brassica 

 oleracea acephala ("choux moellier blanc" of the firm VILMORIN, of 

 Paris) 3 ). During the very wet summer of 1882 it was observable 

 that these stems, more than in other years, underwent a process of 

 voluntary splitting along the longitudinal axis, which even included 

 the vegetation-point of the stem. As a result of this, branching of the 

 stem occurred and true regeneration phenomena also showed them- 

 selves in leaves which had split when very young. There was also a 

 formation of ascidia. 



BEIJERINCK was especially struck with the regeneration symptoms 

 observed in this case, and they led him to experiment on other plants 

 Cryptogams and Phanerogams on "the complete or partial 

 return to the original form after removal of part of the tissue". The 

 observations which he made of the recovery, after wounding, of the 

 tops of the youngest leaves at the vegetation point of a Selaginella, 

 are very interesting. Although the prosenchymatic reinforcing tissue 



') N'dcrhindsch Kruidkundig Archief, 2e serie, 3e deel, 4e stuk, 1882, p. 438-493 

 (Verzamelde Geschriften 1, 90-124). 



i) Bonn 1878. 



i N''.l,Tl;mdsch Kruidkundig Archief, 2= serie, 4e deel, le stuk, 1883, p. 63-105 

 (Verzamelde Geschriften 1, 293-317). 



