Phylum Inophyta [ 129 



nucleate gametes. The germination of the zygote of the Mucorina, by the production 

 of a hypha bearing a sporangium, resembles the production of ascogenous hyphae by 

 the zygotes of Ascomycetes. Two principal changes would convert Mucorina into 

 Ascomycetes: the zygote should cease to be a resting spore, and cell division within 

 the sporangium should be by free cell formation. This could happen if the centro- 

 somes of the ultimate nuclei of the sporangia were in control of cleavage, and if 

 these nuclei were so far separated that considerable areas of cell membrane would 

 lie beyond the influence of the centrosomes, with the effect that the cell membrane, 

 furrowing in to delimit a spore around each nucleus, would leave some of the cyto- 

 plasm outside of all of the spores. The organisms listed below as the first order of 

 Ascomycetes, Endomycetalea, are but poorly known, yet seem genuinely to represent 

 the transition from Mucorina to typical Ascomycetes. 



It is not yet possible to formulate a system of orders of Ascomycetes with the 

 expectation that it will not be found to require much amendment^. The following 

 will serve tentatively; excellent contemporary authority makes several orders each 

 of the ones listed fourth, fifth, and seventh. 

 l.Ascus developed directly from the zygote 

 (or apomictically from an unfertilized cell); 



not producing fruits Order 1. Endomycetalea. 



l.The zygote giving rise to filaments of cells 

 with more than one nucleus, these producing 

 the asci. 



2. Producing fruits. 



3. The fruits cleistothecia. 



4. Asci scattered in the fruits; 

 mostly saprophytes with 



branched conidiophores Order 2. Mucedines. 



4. Asci in one cluster, or solitary, 

 in the fruits; mostly parasites 



with unbranched conidiophores Order 3. Perisporiacea. 



3. The fruits, originally closed, open- 

 ing by irregular pores or regular or 



irregular clefts Order 4. Phacidialea. 



3. The fruits apothecia Order 5. Cupulata. 



3. The fruits perithecia. 



4. Producing a normal mycelium Order 7. Sclerocarpa. 



4. Parasitic on insects, the mycel- 

 ium reduced Order 8. Laboulbenialea. 



2. Not producing fruits, the asci arising di- 

 rectly from the mycelium Order 6. Exoascalea. 



Order 1. Endomycetalea [Endomycetales] Gaumann Vergl. Morph. Pilze 135 



(1926). 

 Subclass Hemiasci Engler Syllab. 26 (1892). 



ILuttrell (1951) has presented a complete reorganization of the class. He sets apart 

 as a major subordinate group Bitunicatae five orders in which the ripe ascus exudes 

 3 vesicle and discharges the spores from this. 



