ARTHUR: PROBLEMS IN THE STupDY OF PLANT Rusts 5 
they certainly appear distinct enough to belong to different genera, 
although now we know them to be forms of one species. The 
ablest writers, down to the days of DeBary at the middle of the 
nineteenth century, described all species of Uredineae under the 
form-genera, each species thus being divided among as many 
genera as it had kinds of spores. Even to the present time the 
practice continues as a matter of convenience. Yet as early as 
1810 Friedrich von Strauss entered a protest against placing such 
obviously connected forms as the Uredo and Puccinia of wheat 
under two genera, but in his attempt to readjust the forms under a 
suitable nomenclature he illustrated what deplorable systematic 
work can be done with a good logical basis but a lack of accurate 
observation. While he believed that many Uredo and Pucciniae 
were genetically connected, he made a vigorous objection against 
the association of certain Aecidia with these forms. In a com- 
munication to the Wetterau Society he says: “The assumption 
that these fungi [%. e., Uredo and Puccinia], at least Uredo segetum, 
originate from the scattered red dust of Aecidium Berberidts, nature 
had already refuted before experience. Numerous examples are 
known to me, where the digging out of barberry hedges did no 
more good than did previously the destruction of crows in the 
American colonies.” I do not know what action was taken in 
these early times against crows in our country, but I know that 
the colony of Massachusetts in the reign of George II. passed a 
law entitled “‘ An Act to prevent Damage to English Grain arising 
from Barberry Bushes,” with very stringent provisions for its en- 
forcement, which law remained on the statute books twenty-five 
years. 
Von Strauss was certainly in error in his conclusion that dig-. 
ging out barberry bushes did no good, as he might have learned, 
had he examined Marshall’s ‘ Rural Economy of Norfolk,” a 
most readable book that had at the time passed through more than 
one edition; and, moreover, he was fundamentally wrong in as- 
suming that there could be no causal connection between such 
apparently diverse fungi as the cluster-cups of the barberry and 
the yellow rust of the wheat, as was proven by DeBary experi- 
mentally a half-century later. 
It is to DeBary that we are indebted for the first clear insight 
