ENTO MOP HT HO RALES (ANCYLISTES) 1065 



The only members of this seemingly omnivorous family which are 

 genuinely aquatic (Ancylistes spp.) are parasitic on desmids. 



ANCYLISTES Pfitzer 



Monatsber. Berlin Akad., 1872: 396. 1873. Emend. Bcrdan, Mycologia, 



30:400. 1938 



(Fig. 91, p. 1066) 



"Intramatrical mycelium consisting of one to several septate, tubular 

 hyphae, variable in diameter, straight or slightly wavy, irregularly 

 branching and anastomosing in the isthmus of the host or sparingly in 

 other places by short lateral branches ; segments of hyphae somewhat 

 swollen, more or less constricted at the cross septa; cytoplasm with 

 numerous rounded, highly refractive granules and somewhat regularly 

 arranged, conspicuous vacuoles; cell walls giving no cellulose reaction 

 with chlor-iodide of zinc. Each external hypha formed as a lateral out- 

 growth from an intramatrical segment; passing through the wall of host 

 as a narrow papilla and emerging as a tubular, occasionally branched 

 hypha into which the content of the internal segment flows and is later 

 cut off posteriorly by a septum; growth of external hypha by progressive 

 flow of protoplasm into advancing tip and the successive formation of 

 cross walls. Asexual reproduction by conidia produced at the tips of 

 the external hyphae or conidiophores and forcibly discharged into the 

 air; conidia spherical, hyaline; columella conical, subtended by a vac- 

 uole and extending into the mature conidium before it is discharged, 

 collapsing afterwards; conidia forming secondary or tertiary conidia 

 directly or germinating by tube; germ tubes functioning as infection 

 tubes or as conidiophores. Formation of conidia suppressed under water, 

 external hyphae functioning as infection tubes. Sexual reproduction by 

 lateral or scalariform conjugation of the contents of unequal game- 

 tangia; zygote formed in a protuberance of the female game- 

 tangium and retracted from its wall; wall of this protuberance smooth 

 or with 9-10 truncate warts; zygote oval, spherical, thick-walled with 

 numerous refractive globules ; germination unknown" (Berdan, he. cit.). 



Parasites of desmids. 



The genus Ancylistes is a small one. It consists of three valid species, 



