424 BOTANICAL GAZETTE [December 



double investment of its oospore, the character of its conidio- 

 phores, and its cytology, probably separated early from the main 

 line of the Peronosporaceae, at a time much later than the diverg- 

 ence of the Albuginaceae from the Peronosporaceae. 



It is a pleasure to acknowledge indebtedness to my wife for 

 the plate accompanying this article. 



College of Agriculture and Mechanic Arts 



Raleigh, N. C. 



LITERATURE CITED. 



Davis, 'go: The fertilization oi Albugo Candida. Bot. Gaz. 29 : 297-311. 

 Hartog, '95 : On the cytology of the vegetative and reproductive organs of 



Saprolegniaceae. Trans. Roy. Irish Acad. 30 : 649. 

 ISTVANFFi, 95 : Ueber die Rolle der Zellkerns bei der Entwickelung der 



Pilze. Ber* Deut. Bot. Gesell. 13 : 456. 

 King, '02 : Fertilization and some accompanying phenomena in Araiospora 



ptdchra, one of the aquatic Phycomycetes. Science 15 : 456. 

 MiVAKE, *oi : The fertilization of Pythm?n de Baryanum. Ann. Botany 15 : 



653-667. 



Stevens, '99: The compound of oosphere of Albugo Bliti. Box. Gaz. 28 : 



149-176. 

 *oi : Gametogenesis and fertilization in Albugo, BoT. Gaz. 32 : 77-9^- 



Tkow, *9g : Observation on the biology and cytology of a new variety of 



Achlya americana, Ann, Botany 13 : 131-179. 

 ^01 : Observations on the biology and cytology of Pythium ulthnufti^ 



n. sp. Ann. Botany 15 : 269-312. 

 Wager, '96: On the structure and reproduction of Cystopus candidus Lev. 



Ann. Botany 10 : 295-342. 

 — '00: On the fertilization of Peronospora parasitica, Ann, Botany 14 • 



263-273. 



EXPLANATION OF PLATE XVIL 



All figures are from material killed in chrome-acetic acid and stained with 

 Flemming's triple stain. The figures were sketched with the aid of an Abb6 

 camera, using the Leitz ^V objective, ap. 1.30. The original drawings gave 

 an enlargement of 1790 diameters, and have been reduced one-third in repro- 

 duction. 



Fig. r. Young oogonium and antheridiura; nuclei in spirem ; wall thick- 

 ened and staining darkly with orange G. 



Fig. 2, Nuclei migrating to periphery ; coenocentrum well developed ; one 

 nucleus in metaphase anchored to it ; peripheral nuclei in advanced prophase. 



% 



V 



