Morphologie etc. — Varietäten, Descendenz, Hybriden. 195 



Der erste Teil beschäftigt sich der Hauptsache nach mit einer oft 

 wörtlichen Wiedergabe der Untersuchungsresultate Altmann's 

 tiber die Anatomie und Morphologie der Kurzwurzel, der zweite 

 Teil bringt die Resultate der eigenen Untersuchungen des Verf. in 

 der Frage des in den Wirtspflanzenzellen beobachteten Endophyten. 

 Es gelang Verf. nachzuweisen, dass diejenigen Gebilde in den Zellen 

 der Kurzwurzeln, die Altmannais Endophyten selbst angesprochen 

 hatte, nichts anderes seien, als die Produkte einer phagoc5^totischen 

 Betätigung des Plasmas der Wirtszellen (Excretkörper), ähnlich wie 

 dies Zach für Elaeagmcs nachgewiesen hatte. Köck (Wien). 



Gates, R. R., Some effects of Tropical conditions on the 

 Development of certain English Oenotheras. (Rep. british 

 Ass. Winnipeg. p. 677—678. 1909.) 



Seeds obtained from England were grown under tropical 

 conditions. The culture consisted of two series of plants, one deriva- 

 tives oi Oenothera Lnrnarckiana , the other derivatives of O. gvandiflora. 

 The former produced a variety of forms, including some quite 

 different from those obtained b}^ de Vries. The majority of the 

 plants continued in the rosette stage throughout the twenty two 

 months during which the culture was prolonged ; cycle after cj'cle 

 of rosette leaves was produced, the older leaves dying away below. 

 Some of the plants ultimately sent up stems of the ordinary type, 

 vv^hich however showed marked fasciation. 



The rosettes of the O. gvandiflora series differ markedly from 

 any of those of the O. Larnarckiana series. Several types of leaves 

 succeed each other as the rosette developes, and in the tropical 

 culture the leaves of the final rosette stage were deeply lobed at 

 the base. This stage is entirely omitted when the plants are grown 

 under ordinary conditions, nor, under such conditions, do the off- 

 spring of the tropical culture exhibit any tendency towards the 

 production of leaves with basal lobes. R. P. Gregor^^ 



Jennings, H. S., Experimental evidence on the effectiveness 

 of selection. (Amer. Nat. XLIV. p. 136—145. 1910 ; 



This paper is a consideration of the "pure line" or genotype 

 concept originated by Johann sen, in its bearings on selection as a 

 possible means of originating new forms. Jennings' own experi- 

 ments with Pavaineciurn show that ever}^ wild race contains many 

 genotypes and that such genotypes may be isolated and show con- 

 stant hereditary differences down to one two-hundredths of a mm., 

 in length. Selection in such cases produces nothing new, but merely 

 isolates existing types, so that the extreme hereditary variations are 

 no farther apart at the end of the selection than the}^ were at the 

 beginning. There has been no progress from "Amoeba to Man". The 

 resulis of various other investigators are shown to ^neld to the same 

 analysis, selection having jäelded nothing beyond the original 

 extremes of Variation. The one exception found is in de Vries 

 selection experiment with buttercups. In this case the extreme 

 number of petals was moved from 11 to 31 and the extreme average 

 from 6 to 13. But other factors may have played a part here. From 

 this point of view the laws of regression and of ancestral inheri 

 trmce lose their physiological significance, and become merely sta- 



