Further Studies on the Apogamy and Hybridization of the Hieracia. 277 



"Diese Thatsache wird erklärlich, wenn man bedenkt, daß die Merkmale 

 der beiden Eltern mit ihrem ganzen Formenkreise aus den Bastard 

 vererbt werden, und daß demnach unter günstigen Umständen der 

 Formenkreis des Bastardes ein beträchtlich weiterer sein kann, als der 

 jeder Eltemsippe eigene" (1. c, p. 63), — an explanation which, in my 

 opinion, does not sa\' anything. Besides, they attribute to the hybrids 

 remarkably small importance for the evolution of the genus: "Bastarde 

 sind vorübergehende Erscheinungen, ihre Befestigung ist nur ausnahms- 

 weise möglich, fast nur dann, wenn ein Bastard zufällig isolirt wird 

 und im Laufe der Generationen vermöge der allgemein geltenden *) 

 Eigenschaft der Bastarde, nach und nach fruchtbarer zu werden, sich 

 dauernd fortpflanzen kann" (1- c, p. 64). These considerations are, 

 however, as hypothetical as those which the authors make on the 

 slight chances of the hybrids for maintaining their existence when 

 growing in company with the parents. As a proof of how difficult it is 

 for hybrids to arise and of how little worth they are for the genus, 

 the authors refer to the fact that in the Botanic Gardens of Munich, 

 "unter den denkbar günstigsten Bedingungen" i), when more than 2000 

 sets of Pilost'lloideae have been cultivated, during 17 years only about 

 70 hybrid combinations have arisen. In the opinion of the authors 

 the hybrids are of value only when the relationship of the species 

 (forms) among one another is to be decided on, — a rather theoretical 

 value, if I may say so. 



The hieraciologists of the present time have, on the whole, more 

 confidence in the importance of the hybrids for the origin of species 

 within this genus, at any rate with regard to the subgenus Pilosella^). 

 But we find no investigations to prove the considerations about the 

 matter, merely casual remarks here and there. 



1) ? c. H. o. 



2) Recently F. Vollmann {1909) has made some considerations on the matter. 

 He is of the opinion that Nägeli and Peter have greatly underrated this species- 

 forming factor. After a short remark on Murbeck's discovery of apogamy in Hie- 

 racium and "die auf demselben Gebiete sich bewegenden Versuche von Ostenfeld 

 und Ravnkiaer" [sie!], he enumerates a whole series of cases, where he thinks it ne- 

 cessary to suppose, that the forms in question have arisen by hybridization, but he 

 lias made no experiments to prove these suppositions. Instead of tliese speculations, 

 which may be correct cnougli, I should have preferred to see some cNprrinients from 

 liim. Purely tlieoreticiil assertions have not much more worth than liis introductory 

 considerations, where among other things he says about "die direkte Bewirkung" 

 [i. e. Lamarckismus], "daß dieser Art von Variation so manche Hieracium-Form ihre 

 Entstehung verdankt, ist so gut wie sicher." 



