BLAKESLEE. — SEXUAL REPRODUCTION' IN THE MUCORINEAE. 231 



bello, N. B., July, '02 ; Keene Valley, Adirondacks, N. Y., September, 

 '02. Professor Thaxter has the species collected by him from Bur- 

 bank, E. Tennessee, 1887, and Mr. A. II. Moore collected it on Mount 

 Washington, September, '02. 



The writer has examined the material from all the localities men- 

 tioned, except that of Harkness and Moore, aiid is able to substantiate 

 the ev4dence of the thallic condition shown in the literature. In all the 

 cases the zygospores are abundant between the gills of the host, and the 

 progametes arise at times from branches of the same hyplia. 



The species is thus homothallic. 



Spinellus sphaerosporus van Tieghem. 



This form, which has been observed only by van Tieghem ('75, p. 75), 

 is similar to S. fusiger in the formation of its zygospores. 



Spinellus chalybeus (Dozy and Molkenboer) Vuill. 



Vuillemin ('04) separates this species from S. fusiger, with which it 

 had been united by Fischer ('92). A tendency toward heterogamy is 

 described, which is indicated by the fact that although the progametes 

 are equal in size, one is of more delicate texture, and after the zygospore 

 is formed, fails to develop a swollen suspensor as does the other. 

 Neither the description nor the figures give us positive evidence as to the 

 thallic condition. None of the five zygospores figured, however, shows 

 the zygophores originating from the same hypha, as is commonly the 

 case in aS". fusiger. 



Spinellus gigasporus Cooke and Massee. 

 This was found by Cooke and Massee ('89) on decaying agarics from 

 Victoria. The zygospores are borne on slender flexuous zygophoric fila- 

 ments. The meagre description tells nothing of the thallic condition. 

 Since, however, it is placed in this genus we may assume that the species 

 in question differs little in this respect from S. fusiger. 



Sporodinia grandis Link. 



This is our most common homothallic species, and has been found by 

 all investigators of the group. The descriptions or figures of Ehrenberg 

 (['20] "29), Corda ('39), Bonorden ('51), de Bary ('64), van Tieghem 

 ('75), Bainier (Q2), Leger ('96), Klebs ("98), Falck ('01), and others 

 agree in making the progametes commonly originate from branches of 

 the same erect filament. Here, as in Spinellus, the connection of the rus- 



