90 MINNESOTA BOTANICAL STUDIES. 



seems a trifle far fetched. More probably the whole head of 

 conidia chains is to be held equivalent to a sporangium. 



Another thing to be considered in this connection is the fact 

 that the Cephalideae are set off from all other Mucoraceae by the 

 manner in which they form zygospores. All the other groups 

 form the zygospore directly by the union of the contents of the 

 two conjugating cells. In the Cephalideae there is a further 

 process. After the tips of the conjugating branches have each 

 cut off by a wall and their contents have united, they do not at 

 once form a zygospore, but the contents contract, separate off 

 from the rest of the new cell by a new wall, and then become a 

 zygospore. Von Tavel remarks, what is not at first apparent, 

 that while the former process is like the conjugation in the 

 Zygnemeae, the latter resembles conjugation in the Mesocarpeae. 

 The relationship of the Cephalideae to the rest of the Mucoraceae 

 must be regarded as somewhat doubtful as far as direct deriva- 

 tive relationship is concerned. There can be no doubt, however, 

 that, wherever their origin is to be found, it "will not be far 

 from that of the other groups. 



Nomenclature. The nomenclature of the group is in a 

 somewhat uncertain state. The names applied by the older 

 mycologists are often of doubtful application, owing to the 

 extreme vagueness and generality of their descriptions. Fischer 

 says: "The laconic brevity of diagnoses formerly favored, 

 makes it often impossible to identify the old forms with those 

 now known, and yet this is necessary, in order that the heavy 

 ballast of doubtful species may be finally thrown off." Dr. 

 Fischer has delivered us from some seventy species of the old 

 authors, and most of the eight American species of 3Iucor must 

 eventually receive like treatment. But while Fischer's work 

 in disposing of the species of the old authors in their 

 proper place has been excellent, he has paid little or no atten- 

 tion to the claims of the names they imposed. The investiga- 

 tors, such as Van Tieghem, often took little pains to ascertain 

 the identity of the forms they worked upon with those named 

 by the earlier writers who only described, and imposed names 

 now current upon several forms which had already received 

 more than one name. 



Mycologists have differed on the question of the respect to 

 be paid to priority quite as much as phanerogamists. Winter 

 in Part I of the Pilze in the Kryptogamen Flora v. Deutschland, 

 etc., applied the rule of priority vigorously, but somewhat 

 capriciously. Schroeter has consistently adhered to it. Sac- 



