128 THE LOWER FUNGI— PHYCOMYCETES 



a single thallus, but conjugating segments arise from different 

 thalli. As a result of conjugation a spherical "oospore" is formed 

 in one segment of each pair. 



The species has been studied by Dangeard (1906) and Maupas 

 (1915). The former author saw it only in the sporangial stage, 

 and regarded it as one of the Hemiascales. The reasons for 

 incorporating the genus in the Ancylistales are discussed by Maire 

 (1915). He suggests that the fungus be made the basis of a new 

 family, Protascaceae, which he regards as intermediate between 

 the Lagenidiaceae and Ancylistaceae, The erection of the new 

 family seems premature in the light of our incomplete knowledge 

 of the order, while the small size of the group makes it unneces- 

 sary. The name, Protascaceae, is unfortunate, in that the group 

 may easily be confused with the Protascales of the Ascomycetes. 



The writer is not convinced that Protascus is closely related 

 to the other genera incorporated in the Ancylistales, and its 

 inclusion here is at best tentative. At present, no more satis- 

 factory disposition of it seems possible. 



6. Lagena Vanterpool & Ledingham (1930: 192). 



A monotypic genus, recently erected on L. radicicola Vanter- 

 pool & Ledingham, an obligate parasite in rootlets of cereals in 

 Sashatchewan. Mycelium is absent. The thallus is unicellular, 

 unbranched, ovoid to cylindrical, sometimes curved, and is 

 attached to the host wall by a neck. It may function as a 

 sporangium or "coenogametangium." The contents of the 

 sporangium escape into a thin-walled vesicle, in which bean- 

 shaped, laterally biciliate swarmspores are formed. Thalli 

 functioning as "coenogametangia" conjugate in pairs by means 

 of a tube, and a thick-walled "oospore" recalling that of Pythium 

 is formed. Apparently the genus lies near Lagenidium. 



BIBLIOGRAPHY: ANCYLISTALES 



Atkinson, G. F., Some fungous parasites of algae. Botan. Gaz., 48: 321- 



338, fig. 1-8, 1909. 

 , Some problems in the evolution of the lower fungi. Ann. Myc, 7 : 



441-472, 1909. 

 BoRzi, A., Rhizomyxa, nuovo ficomicete. 53 pp., 2 pi., Messina, 1884. 

 Dangeard, P.A., Note sur la germination de I'oospore de TAncylistes 



closterii. Bui. Soc. Linn. Normandie, 10: 1886. 

 , Recherches sur le d6veloppement du perith^ee chez les ascomycetes — 



I. Les ancetres des champignons sup6rieurs. Le Botanists, 9 : 207-226, 



pi. 2-8, 1906. 



