(52) 



FAMILY PETROMYZONTIDAE. 

 Genus Petromyzon^ Linn. 



154. P. niqer^ Raf. Small Black Lamprey. Very common in 

 many localities through northern Illinois, ascending small streams in spring 

 from Lake Michigan and the rivers. 



Genus Iclithyomyzon, Gir. 



155. /. argenteus, (Kirf.) Grd. Silvery Lamprey. Lake Michigan 

 and large rivers throughout the state. 



156. I. hirndo, Grd. A single specimen in the state collection from 

 the Ohio at Cairo. 



UPOlSr PARASITIC FUNG-I. 



BY T. J. BURRILL, 



(Professor of Botany and EorticuUure in the Illinois Industrial University.) 



Many doubt the action of microscopic fungi in causing diseases of 

 higher plants and animals. Indeed it has only been in our century, and 

 mostly in the latter part of it, that botanists have distinguished these 

 minute parasites as independent plants. Schleiden (1) in a work written 

 about 1845 said, " I cannot regard the true Uredines, etc., {Coniomycetes) 

 as independent plants. Meyen r2) observed the formation of Uredo mnidis 

 as an abnormal process of cell formation in the interior of the cells of the 

 parent plant; and, in this respect, my own observations on Elynius arena- 

 rius coincide with his." Unger (3) in 1833 sought to prove that the so-called 

 fungi were changed conditions of diseased tissues ; and Fries in a classic 

 work upon fungi, holds similar views. 



But the matter is not left undecided The improvements in micro- 

 scopes, and in methods of tracing the life history of low organisms, have for- 

 ever settled the doubts in the minds of scientific men. Nothing can be more 

 satisfactory in the way of evidence, than to see with one's own eyes the spores 

 germinating, penetrating the plant tissues, and in due time producing again 

 spores like the ( riginal ones. This has been done again and again, and may 

 be seen by any one who will take the trouble to follow, day by day, the de- 

 velopment of any of the hundreds always and everywhere at hand. Their 



1. Principles of Scientific Botany. London, 1849, p. 151. 



2. Ueber die Entwickelung des Getreidebrandes in derMais-Pflanzen, Weig- 

 mans Archiev., 1837, p. 419. 



3. Die Exantheme des Pflanzen, Wein, 1833, p. 356. 



