Cytologie und Befruchtung. 291 



entwickelt; beide sind unverzweigt und im zweiten Jahre noch 

 am Leben. Grevillius (Kempen a. Rh.). 



Arthur, J. C Taxono mic Importance of the Spermo- 

 gonium. (Bulletin Torrey Botanical Club. XXXI. p. 113 

 — 123. March 1904.) (Read before the American Association 

 for the Advancement of Science, St. Louis. Dec. 30, 1903.) 



At the beginning Dr. Arthur disclaims all Intention of 

 treating the subject from any knowledge of the true nature of 

 the spermogonium and that although the name implies a sexual 

 function either active or obsolete, proof of such function is lacking. 

 Cytological evidence shows very distinctly that the spermo- 

 gonium is an organ in no wise comparable with the uredo- 

 sorus or the aecidium. The spermatia from the spermo- 

 gonium are uninucleate, and both the aecidiospores and uredo- 

 spores are binucleate, the two latter are now beyond a doubt 

 asexual conidia in function. The nuclear cycle may be stated 

 as lollows: A fusion of nuclei takes places in the teleutospore 

 having the physiological effect of a sexual act, and establishing 

 the beginning of the nuclear cycle. During germination the 

 one nucleus thus formed divides into four, one for each of the 

 four sporidia. By the time the sporidium is ready to form a 

 mycelium, its nucleus has separated into two, lying side by 

 side, and hence forth these paired nuclei maintain an indepen- 

 dant existence, when a new cell of the mycelium or a conidio- 

 spore is formed, each of the paired nuclei divides, half of each 

 remaining in the old cell, and half going to the new one, Thus 

 the two associated nuclei have an independant line of descent 

 from the time of leaving the sporidium of the germinating 

 teleutospore until they arrive in a teleutospore again. Thus 

 the life-cycle of a rust begins with the germinating teleutospore, 

 that is the sporidium; the spermogonium is a problematical 

 organ, and all other sorts of rust spores are of a conidial or 

 asexual character. 



It is further shown that in the succession of spore forms, 

 the spermogonium is usually present following the germination 

 of sporidia even when aecidiospores or uredospores or both 

 are lacking in the series following, Thus the common con- 

 ception of the spermogonium as an accompaniment of the 

 aecidium, or other spore-forms is incorrect, 



Spermogonial characters have little or no generic value, 

 but their specific value is shown to be considerable, first as 

 an indication of the nature of the life cycle, and secondly as 

 furnishing positive characters for identification. Hedgcock. 



Leavitt, R. G. and L. J. Spalding, Parthenogenesis in 

 Antennaria. (Rhodora. Vol. VII. p. 105. June 1905.) 



Note on the formation of embryos directly from egg cells, 

 without fertilization in Antennaria fallax and A. neoclioica. 



H. M, Richards (New York). 



