CONTRIBUTIONS FROM THE CRYPTOGAMIC LABORATORY OF 

 HARVARD UNIVERSITY. — LVIII. 



SEXUAL REPRODUCTION IN THE MUCORINEAE. 



By Albert Fkaxcis Blakeslee. 



Presented by R. Thaxter, Maj- 11, 1904. Received May 11, 1904. 



PREFACE. 



For several years past the writer has been engaged in a study of the 

 Mucoriueae, which he at first intended should comprise a general survey 

 of the morphology and development of the group, and include at least an 

 attempt to set in order some of the confusion in which the systematic 

 study of these plants has been involved. Having accumulated a con- 

 siderable amount of material for the purpose, the greater part of which 

 has been kept under cultivation in pure cultures, he was led about a 

 year since to abandon his original plan and restrict his field of investi- 

 gation to a single phase of the subject in hand, and to confine his attention 

 to the conditions influencing, or associated with, the production of the 

 so-called " sexual spores," or zygospores, which are characteristic of 

 these fungi. Although during the past thirty or more years this subject 

 has received much attention from botanists, and has been the object of 

 numerous researches, the results obtained in the present instance appear 

 to be quite novel, and, in the writer's opinion, present for the first time a 

 rational basis by means of which the phenomena of sexual reproduction 

 in the group may be explained. 



That the present paper, which is practically based on hardly a year's 

 work, embodies a necessarily inadequate treatment of the subject need 

 hardly be pointed out ; but although the necessities of the case have 

 rendered this incomplete presentation unavoidable the writer proposes to 

 continue his inve.^tigatious, and trusts that he may be able in a future 

 communication to remedy in some measure the deficiencies of the 

 present one. 



It is a pleasurable duty to acknowledge at this place indebtedness to 

 those who have kindly given assistance in one way or another : to Dr. 

 W. G. Farlow for the use of his herbarium and for several of the papers 



