88 TEXT-BOOK OF FUNGI 



adhering to them. Afterwards the trichogyne soon withers 

 and disappears. The non-motile antherozoids are minute 

 cylindrical bodies, endogenous or exogenous in origin. 

 Endogenous antherozoids, so far as is known, are confined 

 to two aquatic genera. The antheridia are usually so 

 placed that the antherozoids are liberated very near to, or 

 actually upon, the trichogyne, to which they adhere. After 

 fertilisation the carpogenic cell divides into several cells ; 

 some of these cells, the ascogenic cells, begin to bud, 

 the buds developing directly into asci. The asci contain 

 either four or eight spores, and deliquesce at an early stage 

 as in many other Ascomycetes, liberating the spores in the 

 perithecium, from which they escape at maturity. The 

 perithecium originates from a cell placed below the asco- 

 gonium. The behaviour of the nuclei during fertilisation 

 and afterwards is not known. 



The mode of fertilisation described above agrees in all 

 essential features with that presented by the Florideae, and 

 some Lichens. Similar trichogynes, more or less aborted, 

 also occur in other groups of the Ascomycetes, as in 

 Xylaria, Poronia^ etc. 



Blackman has described what he considers to be a process 

 of fertilisation in the aecidium of Phragmidium vtolaceum, 

 one of the Uredineae. From the mass of vegetative hyphae 

 constituting the first evidence of an aecidium, those cells 

 immediately beneath the epidermis increase in size and 

 become divided by a transverse wall, each cell containing 

 a single nucleus. The upper cell is a sterile cell and soon 

 disappears. The lower cell becomes binucleate, and 

 eventually produces a series of binucleate aecidiospore 

 mother-cells. The problem as to how the lower or fertile 

 cell became binucleate was solved by the discovery of a 



