230 The Anatomy of Plants BOOK u 



and the state of knowledge based upon them form the 

 groundwork of De Bary's great work of 1866, to which 

 reference has already been made. This was supplemented 

 by its author in 1884, in a second edition, greatly extended 

 or rewritten, which was the great textbook of our period. 

 Many important memoirs during the period under review 

 extended knowledge of life-histories, brought to light many 

 facts bearing on pleomorphy, and cleared up many problems 

 connected with sexuality and reproduction. So great was 

 the increase of memoirs and other publications that no 

 satisfactory provision for final classification was arrived 

 at, the mass of detail needing careful scrutiny and dis- 

 cussion when the century closed. 



Among the numerous contributions to the literature of 

 the subject, some stand out naturally more prominently 

 than others, either by bringing out new life-histories, or 

 by correcting erroneous views of the nature of various 

 processes. 



The Myxomycetes were investigated by De Bary and his 

 pupils from 1860 to 1870, and their processes of fructifica- 

 tion ascertained. A few years later Schmitz showed that 

 the union of the amoeboid masses to form the plasmodium 

 is not a species of conjugation as had been long held, for 

 no fusion of their nuclei takes place. Lister was successful 

 in 1888 and 1889 in showing that the nuclei divide karyo- 

 kinetically. Towards the end of the century the question 

 of their real affinity with the animal rather than the 

 vegetable kingdom was a subject of discussion. 



The parasitism of many of the Phycomycetes was studied 

 by various workers, and considerable inquiry was made into 

 their sexuality. De Bary concluded that the Saprolegniae 

 at any rate are always parthenogenetic. The cytology of 

 the group was examined by Pfitzer (1872), De Bary and 

 Woronin (1881), Hartog (1887 and 1896), Rothert (1887), 

 and Trow (1895). In 1889 Wager studied the behaviour 



