96 ALBERT FRANCIS BLAKESLEE. 



Judged by their reaction with the (+) and ( ) strains of 

 Mucor V., the forms Z. Moelleri, Z. Vuillemini and Z. Vuillemini 

 agamus have a male tendency, while Z. heterogamus has a female 

 tendency. It is in harmony with this classification that Z. 

 Vuillemini agamus produces azygospores in contact with Z. 

 heterogamus (Fig. 29). 



SUMMARY 



It has been shown that sexual reactions called "imperfect 

 hybridization " may occur when hermaphroditic species of Mucors 

 are grown in contact with the sexual races of dioecious forms. 

 Certain of these hermaphrodites are heterogamic, showing a 

 constant difference in the size of their gametes. It is assumed 

 that the larger gamete is female and the smaller one male. The 

 race of dioecious Mucors provisionally called (+) shows a sexual 

 reaction with the smaller or male gamete while the ( ) or 

 vegetatively less vigorous race shows a reaction with the larger 

 or female gamete. It. is concluded therefore that the ( + ) race 

 of dioecious Mocurs is female and the ( ) race, male. 



BIBLIOGRAPHY. 

 Blakeslee, A. F. 



'043 Zygospore Formation a Sexual Process. Science, N.S., 19: 864-866. 

 'O4b Sexual Reproduction in the Mucorineae. Proc. Am. Acad., 40: 205-319. 

 'o6a Zygospore Germinations in the Mucorineae. Annales Mycologici, 4, 1-28. 

 'o6b Differentiation of Sex in Thallus, Gametophyte and Sporophyte. Bot. 



Gaz., 42: 161-178. 



'09 Papers on Mucors. Bot. Gaz. 47: 418-423. 

 '133 Conjugation in the Heterogamic Genus Zygorhynchus. Mycologisches 



Centralblatt, 2: 241-244. 

 'i3b A Possible Means of Identifying the Sex of (+) and ( -) Races in the 



Mucors. Science, N.S., 37: 880-881. 

 Hagem, Oscar. 



'08 Untersuchungen iiber Norwegische Mucorineen. Vidensk.-Selsk. Skrif- 



ter. I., Math.-Nat. Kl., pp. 50. 

 Lendner, Alf. 



'08 Les Mucorinees de la Suisse. Materiaux pour la flore cryptogamique Suisse, 



Vol. III., Fasc. I., pp. 180. 

 Moreau, F. 



'12 Sur la reproduction sexuee de Zygorhynchus Moelleri. C. R. Soc. Biol., 



73. P- 14- 

 '13 Recherches sur la reproduction des Mucorinees et quelques autres Thallo- 



phytes. Poitiers, pp. 136. 

 Namyslowski, B. 

 "10 Studien iiber Mucorineen. Bull. Acad. Cracovie, 477-520. 



