78 
Wisconsin Academy of Sciences, Arts, and Letters. 
6. duel. Die Kerntheilung in den Basidien nnd die Phylo¬ 
gon ie der Basidiomyceien. J ahrbiicher fiir wissen- 
schaftliche Botanik. Bd. XXXII, lift. 2. 
7. Smith, Grant. The Hanstoria; of the Erysipheae. Bot. 
Gazette, Mch., 1900. 
8. Strasbnrger. Zellbildnng nnd Zelltheilnng. p. 288. 
9. Mottier, David M. Xnclear and cell division in Dictyota 
dichotoma. Annals of Botany. June;, 1900. 
10. Klebahn. Ueber die Zygosporen einiger Oonjugaten. 
Bor. d. d. botan. Ges. 1888, p. 160. 
11. Schmitz. Untersuchungen iiber die Struktnr des Pi*oto- 
plasmas nnd d. Zellkerne d. Pflanzenzelle. Sitzb. d. 
neiderrheinischen Gesellschaft fiir Xaitnr nnd Heil- 
knnde in Bonn, 1880. 
12. Rosen, E. Stndien iiber die Kerne nnd die Membranbild- 
nng bei Myxomyceten nnd Pilzen. Cohn’s Beitr. 
znr Biol. d. Pdanzen. Bd. VII, 1892. 
13. Ilaecker. Die Vorstadien der Eireifnng. Archiv fiir 
mikroskopische Anatomic. XLV., 2. 
EXPLANATION OF PLATE I. 
All figures were drawn with the aid of the camera lncida. 
Eig. 1. x 196. T'elentospore sorus of Coleosporium sonchi- 
arvensis. The mycelium and hanstoria 
are shown binncleated. At the extreme 
left are shown two teleutospores in which 
nuclear fusion has not yet occurred. At 
the right is another teleutospore. In 
most of the cells nuclear fusion has oc¬ 
curred and the teleutospore has developed 
into a promyceliuin. In twoi instances 
the promycelium, lias- become two celled. 
In other cases it has become four celled. 
In one case one of these divisions has al¬ 
ready formed a sterigma and passed 
through the epidermal sorns cover and 
the second division is in* the act of pass¬ 
ing. 
