THE RESULTS OF SELECTION WITHIN PURE LINES OF 

 PESTALOZZIA GUEPINI DESM. 1 



CARL DOWNEY LA RUE 



University of Michigan, Ann Arbor, Michigan 



Received June 30, 1921 



TABLE OF CONTENTS 



INTRODUCTION 1*2 



Reason for the choice of Pestalozzia 145 



Experiments 1*0 



Methods and conditions 150 



Selection of spores according to their progeny 



Experiment 1. Selection for length of spores 158 



Experiment 2. Selection for length of spore appendages 162 



Selection of spores according to visible characters 167 



Experiment 3 168 



Experiment 4 172 



DISCUSSION 174 



CONCLUSIONS 182 



LITERATURE CITED 182 



APPENDIX TABLES 184 



INTRODUCTION 



Since JOHANNSEN'S classic experiments on beans led him to formulate 

 his theory of the multilinear composition of species and the inefficacy 

 of selection within any of the lines, several workers have studied the effect 

 of selection within pure lines of various other organisms. No apology need 

 be offered, however, for this extension of the work to one of the asexually 

 reproducing Fungi Imperfecti, for the peculiarities of the material make 

 possible a quite different experimental attack. Inasmuch as the literature 

 of the selection problem has recently been thoroughly reviewed by 

 JENNINGS (1916, 1920). and others, only those papers will be considered 

 here which have special bearing on the present investigation. 



One of the most noteworthy of such contributions is that of JENNINGS 

 (1908) on Paramecium. In a carefully planned and executed series of 

 experiments in which numerous selections were made, JENNINGS was unable 



1 Papers from the Department of Botany of the UNIVERSITY OF MICHIGAN, No. 186. A 

 portion of this investigation was carried out at Kisaran, Asahan, Sumatra; the remainder in 

 the Botanical Laboratory of the UNIVERSITY OF MICHIGAN. 



CiEN-ETics 7: 142 Mr 1922 



