75 



RiNCK concluded in that year that he had to end these experiments. 

 Either the conditions in Delft were unfavorable for cross-breeding 

 experiments, or Beijerinck's attention there was taken up by too 

 many other problems to allow time for such experiments. 



On the experiments with Triticum species just indicated, there have 

 appeared two small pubhcations in the German language, in 1 884 and 

 1886 respectively ; both pubhcations appeared in the Ned. Kruid- 

 kundig Archief. The results of only a part of his experiments were 

 given. This may appear from the large collection of wheat ears 

 (unfortunately not in a carefuUy-preserved condition, and without 

 notes) which Beijerinck kept for many years, and which finally 

 came into the possession of the Laboratory for Technical Botany at 

 Delft. The wonderful drawings of flowers and ears of wheat-species 

 present in his collection of plates prove how deep his studies on cereals 

 have been. 



After what has been said about Beijerinck's lecture, we must call 

 attention to the f act, however, that both pubhcations were written in 

 the first place to throw a light on a scientific problem, namely, the 

 origin of the cultivated species of wheat. By determining which cross- 

 breedings were possible, which succeeded incompletely, and which 

 produced no result, he considered it possible to gain an insight into 

 the relationship of these species. From this Beijerinck also expected 

 to gain practical consequences ultimately. 



In the first-named publication i) Beijerinck discusses a bastard 

 obtained by him by cross-breeding Triticum monococcum (the "Ein- 

 korn") as the mother plant, with Triticum dicoccum (the "Emmer") 

 as the father plant. Both plant forms were descended from seed ob- 

 tained from H. ViLMORiN in Paris; of the first species the variety 

 "engrain doublé", that is, "das doppelte Einkorn", called Tr. mono- 

 coccum f lavescens by KöRNiCKE, was used; of the second species, the 

 variety "amidonnier blanc", that is Körnicke's "der weisse, kahle, 

 begrahnte Emmer". 



The bastards developed into strong plants, rather resembling the 

 mother plant in their vegetative organs, and the male plant in the 

 generative organs. The excellent drawings of the ears, spikelets, and 

 the calyx chaffs, which Beijerinck added to the treatise, illustrate 

 many details very clearly. The most important point for Beije- 

 rinck's considerations was that the bastards appeared to be com- 

 plet ely sterile, for he concluded therefrom in his first treatise that Tr. 

 monococcum and Tr. dicoccum are not related forms. The opinion that 

 these cultivated species were derived from one common wild form — 

 de Candolle considered this probable for all cultivated cereals — 

 was shaken, therefore, by this observation. 



») Ueber den Weizenbastard Triticum monococcum $ x Triticum dicoccum ^, Ne- 

 derlandsch Kruidkundig Archief, 2e serie, 4e deel, 2e stuk, 189-201, 1884 {Verzamel- 

 de Geschriften 1, 401-408). 



