214 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in inverse proportion to one another. In the simplest form of sexual 

 reproduction (Mucor Mucedo, Sporodinia grandis) there is only one kind 

 of sporangium. Then come forms with two kinds of sporangia, either 

 on the same or on two kinds of sporangiophore (Thamnidiuni), ordinary- 

 sporangia and smaller sporangioles, the latter reverting to one-spored 

 closed sporangia or conidia. In Choanephora both kinds of sporangia 

 occur on distinct sporangiophores ; in Chsetocladium, &c, sporangioles 

 only are formed. The conidia can also take up an oidium form by 

 septation, as in Piptocephalis. A further complication takes place 

 when the sporangiophores are produced only on stolons. 



Among the very numerous forms of the Zygomycetes that have been 

 investigated, there is at present only one species known, Sporodinia 

 grandis, in which the sexual sporangiophores and the zygotes are pro- 

 duced with the same frequency, or nearly so, as the non-sexual sporangia. 

 The formation of one or the other kind of fructification is largely de- 

 pendent on the supply of water ; and the same was found to be true 

 also in regard to other Zygomycetes — Phycomyces, species of Mucor and 

 Chlamydomucor, Phizopus, Thamnidium, Chsetocladium, Ac. 



The author regards the higher non-sexual families of Fungi, such as 

 the Basidiomycetes, as not so much non-sexual as apogamous forms, in 

 which the production of zygote or other sexual organs has gradually 

 died out. This view has been obscured by the mistaken theory that the 

 " spermatia " of the LaboulbeniaceaB and other families are degenerated 

 male sexual organs ; they are simply a special form of conidium. 



Cladochytrium Alismatis. * — A detailed study of this fungus has 

 been made by G. P. Clinton on material collected at Cambridge, Mass. 

 It has been found in various parts of Europe on the leaves, &c, of 

 Alisma Plantago, but this is its first record for America. The author 

 succeeded in germinating the fungus and reinfecting young seedlings of 

 Alisma ; he was thus able to follow every stage in the development of 

 the Cladochytrium, and to determine the existence of a temporary 

 sporangium. The different stages are well illustrated. Mr. Clinton at 

 the same time obtained Cladochytrium Menyanthis, and germinated its 

 sporangia, but the fungus would grow neither on Alisma nor on various 

 algae, and as plants of Menyanthes were not available for infection, 

 further investigation of that species was impossible. 



New Genera and Species of Laboulbeniaceae. f — Together with a 

 number of new species, It. Thaxter now describes the following new 

 genera of Laboulbeniaceae. 



Eumonoicomyces g. n. (separated from Monoicomyces). Receptacle 

 consisting of a basal and sub-basal cell ; the latter producing terminally 

 a sterile appendage, and laterally usually one fertile branch, the axis 

 of which is coincident with that of the receptacle, from which it is 

 not distinguished, and consists of a series of superposed cells, which 

 may bear a sterile appendage, an antherid, or an antherid and a peri- 

 thece. The antherid consists of a single stalk-cell and a single, often 

 obscure, basal cell ; the body of the antherid consists of a series of 



* Bot. Gaz., xxxiii/(1902) pp. 49-61. 



t Proc. Airier. Acad. Arts and Sci., xxxvii. (1901) pp. 21-45. Cf. thia Journal, 

 1901, p. 565. 



