350 



plant were pertectly constant. Tliey all possessed quile the habitns 

 of the intermediary Form. That the plant in qnestion cannot be a 

 true hybrid, bnt had piobably arisen from a seed of another ele- 

 mentary species which cannot be discussed here, was however, 

 only demonstrated with certainty by the examination of the 

 generative nuclei. 



My thanks are due to Dr. Lotsy who, in the spring of 1921, 

 gave me part of his material for the purpose of repeating the ex- 

 periment of cross-fertilization, fuither cultivation of the plants, and 

 cytological examination to ascertain the cause of the constancy. 



My own experiments in cross-fertilization also yielded only plants 

 which were the same as tiie mother plant. The luilluies of E. cock- 

 leoUles and of E. vioitceo-petiolitta, as well as those of the inter- 

 mediate form which was first talven to be a hybrid, but which, 

 since it appears that this is nut the case, 1 will now term Ërophila 

 confertifolia on account of its extremely close roset of leaves, remained 

 perfectly constant in the years 1922 and 1923'). The results of the 

 attempts at cross-fertilization soon suggested to Dr. Lotsy the possi- 

 bility of apomixy. This would not agree with the results obtained 

 by RosKN, but if correct it might explain why his J^ropAiVa'^ remained 

 constant in the P\. 



The following notes upon the results I obtained will prove that 

 the sup|)Osition of apomixy was correct and that apogamy ') played 

 a part in the affair. 



As regards the methods, it must be remarked that the best pre- 

 parations were obtained by fixing with chloroform-alcohol-acetic acid 

 after Carnoy. The sections, after being imbedded into paraflt'in, were 

 made with a Reinhold-Giltay microtome to a thickness of 5 /n. 

 The colouring was done with Heidenhain's haematoxylin. 



Like all elementary Erophila species hitherto described, which 

 were found together at the same place, the sub-species here treated 

 exhibit, besides points of great difference, also a great similarity, which 

 a very close systematic relation suggests. E. cochleoides is the smallest 

 of the three, possesses short spatnlate leaves, slightly narrower 

 towards the base and only in the older stadia showing a shallow 

 denticulation. The stalks are strong but not of great length. On 

 the other hand E. confertifolia possesses longei' and softer stalks 



1) Although the plants have not yet flowered, the constancy can be proved with 

 a fair degree of constancy from the young rosets. 



') .Apogamy" is employed here in the definition of Stkasburger, i. e. develop- 

 ment of an unfertiiazed diploide ovule; according to Winklkr this is a question 

 of somatic parthenogenesis. 



