242 



Ostenfeld. 



facts which, in my opinion, are rather interesting and wiiich I think 

 worthy of publication. They touch upon both problems, apogamy 

 and hybridization. 



As to the apogamy, a species has been found whose "races" differ 

 in this respect, and we have here, in all probability, the apogamy 

 in statu 7iascendi. And with regard to the hybridization it has 

 become apparent that the first hybrid generation (Fj) affords such a 

 complexity of combinations of the characters^), while the later hybrid 

 generations (Fg, F3, etc.) breed true, that — for ihe one subgenus — 

 an understanding of the famous polymorphy of the genus is suggested. 



A good deal of the following remarks may perhaps seem frag- 

 mentary; this is due, at least in part, to the fact that several ex- 

 periments have failed, and that transplanting and the like have checked 

 the investigation. Moreover, I have been away from the Gardens part 

 of the summer every year, and the summer of 1909 was so unu- 

 sually rainy and cold as to greatly influence the thriving of the 

 delicate species. 



My friend. Dr. O. Rosenberg of Stockholm has, as before, taken 

 his share in the experiments in that he has had collected materials for 

 cytological use of all my experimental plants. I only need to point 

 to his well-known cytological investigations on the Hieracia (RosEX- 

 BERG 1906, 1907), in order to sliow the benefit I have had from his 

 excellent collaboration. 



I. 

 Apogamy. 



(Castration Experiments.) 

 In 1906 I summed up the results of m}' experiments on the 

 apogamy of the Hieracia in the following way (1. c, p. 235): — ,,In 



1) H. Winkler (1909, p. 342) has advanced the theory: ,,Es scheint demnach, 

 als sei es ein wesenthcher Unterschied des Pfropfbastardierungsprozesses von dem 

 sexuellen Bastardierungsprozeß und für ihn besonders charakteristisch, daß er 

 nicht wie dieser eine im wesentlichen homogene, sondern eine vielgestaltige Gene- 

 ration Fl liefert'', and Strasburger (1909 b, p. 519) seems to agree with him herein 

 and expresses himself still more explicitly, saying: ..Pfropfbastarde, denen zudem die 

 besondere Eigenschaft zukommen si 11, daß sie nicht homogen wie sexuelle Bastarde, 

 sondern vielgestaltig sind", and further: ,, Derartiges [verschiedene Kombinationiu 

 der Merkmale] ist für sexuelle Bastarde nicht bekannt." Both authors must have 

 forgotten that heterogeneity in Fi has been found in several cases in sexual hybrids,, 

 e. g. in Rubwi and, already discovered by Mendel, in Hieracitim. It is therefore not 

 a special property of the supposed grafting hybrids. 



