Further Studies on the Apogamy and Hybridization of the Hieracia. 271 



The first who touched upon this apparent relation of apogamy 

 to polymorphism, was Sv. MurbecK, who as early as 1897 (p. 277) 

 — he accentuates it a little too strongly later (1904, p. 295) — 

 has intimated that for the Alchimilld's there must be a certain relation 

 between the constancy shown by the apogamy and the polymorphism. 

 His words, however, are very vague. Having mentioned that the 

 reason for the great constancy of the AlcJiimilla species has to be 

 sought in the apogamic development of the seeds, which is really to 

 be considered as a kind of layer-formation, he says that in a later 

 detailed cytological investigation he will perhaps also have occasion 

 to express himself "on a question at present obscure, how the poly- 

 morphism now ruling within the genus has come about. For that, 

 however, is required an exact knowledge of the geographical distribution 

 of the forms"!). 



Somewhat more fully and decisively Raunkiaer expresses him- 

 self (1903, p. 136 — 138) about the Taraxacum species. From the fact 

 that all the species examined by him, which have widely different 

 geographical distributions, are apogamic, he concludes "that the power 

 of forming seeds without fertilization has originated in Taraxacum be- 

 fore this genus was split into many species and that the existing 

 species have originated without any fertilization or crossing"^). If 

 this conclusion is right, he thinks that in Taraxacum we have a genus 

 which may be of importance for the study of the origin of species, 

 and that future investigations on the species and their geographical 

 distribution will contribute to the solving of the question, whether the 

 origin of species has been occasioned in the Lamarckian way or in 

 the Darwinian way (inch that of mutation). 



In his paper on apogamy in Taraxacum and Hieraciiim Murbeck 

 (1904) — as already mentioned • — comes back to this problem, 



the mutants of Lamarckiana, is partly apogamic, "though only in a small percentage 

 of cases". But "this indication of apogamy in O. lata of course requires to be 

 substantiated by a more detailed study". 



Mrs. R. Haig Thomas has recently (1909) published a short paper on ..Partheno- 

 genesis in Nicotiana", and probably we have here a new case of apogamy, which 

 agrees well with the relation-theory, as Nicotiana is a critical genus. 



1) "om ett annat for närvarande dunkelt spörsmäl, huru den nu rädande poly- 

 morfismen inom släktet i-n gang kommit til stAnd. Härför erfordras emellertid en 

 noggran kännedom om forraernas geografiska utbredning". 



^) 'at Evnen til at danne Kim uden Befrugtning er opstaact hos Taraxacum, 

 for denne Slaegt er blevet spaltet i flere Arter, og at de existerende Arter er opstaaet, 

 uden at Befrugtning og Krydsning har spillet nogen Rolle". 



