288 THE LOWER FUNGI— PHYCOMYCETES 



The genus Delacroixia Constantin (1897), known only in the 

 conidial phase, is clearly very closely related to Conidioholus. 

 It contains the single species, D. coronata Constantin, found 

 growing as a saprophyte on the gills of mushrooms and on orchid 

 seed. Gallaud (1905) has studied the form in culture in nutrient 

 solutions and on various soUd media. Until its resting spores 

 are discovered its position will remain somewhat in doubt. 



3. Completoria Lohde (1874). 



The genus Completoria contains a single species, C. complens 

 Lohde, parasitic on prothallia of various ferns. It has been 

 studied extensively by Leitgeb (1881) in Europe and by Atkinson 

 (1894) in America. 



The vegetative portion of the fungus consists of a more or 

 less compact botryose cluster of short, oval, or somewhat curved 

 hyphal branches originating from a common center and present- 

 ing on the surface a convoluted appearance (Fig. 104). This 

 vegetative body is confined at first to a single host cell, and is 

 often small and inconspicuous, being composed of only a few 

 branches closely recurved upon the parent hyphae. At times it 

 is larger, completely filling even a large host cell. At maturity 

 it usually spreads to neighboring cells, certain peripheral branches 

 merely putting out slender threads which pierce the intervening 

 walls. Such a thread on reaching the center of the new cell 

 cavity enlarges at its tip to form an oval body into which the 

 protoplasm of the parent cell flows. This oval enlargement then 

 puts out short protuberances which become enlarged at a short 

 distance from their point of origin, undergo branching, and soon 

 give the botryose appearance of the parent thallus. 



Under certain conditions the fungus produces resting spores. 

 They are formed in the interior of the thallus, ten or more often 

 being found in a compact group surrounded by the smaller, 

 terminal, then empty, peripheral branches. The resting spore 

 is globose to oval, and at maturity is provided with a smooth, 

 three-layered wall. Its sexual nature has not been demonstrated. 

 Asexual reproduction by means of aerial conidia sometimes 

 occurs. The conidia in their shape and method of formation 

 resemble those of other members of the order, and at maturity 

 are forcibly ejected. Inclusion of the genus in the Entomoph- 

 thorales rests chiefly on a consideration of the conidial stage. 

 I'he resting spore, though tentatively termed an oospore by 



