THALLOPHYTA— FUNGI 83 



many forms the trichogyne is wanting, and only the coiled por- 

 tion is found. The male organ is sometimes a poUinodium, 

 mueh like that of the preceding group, and produced in the 

 immediate neighbourhood of the carpogonium. Sometimes it is 

 a filament producing small cells by abstriction. These fila- 

 ments are known as sterigmata, and are borne in special 

 depressed receptacles called spermogonia [figs. 836 and 837). The 

 separate cells correspond to antherozoids, but are incapable of 

 motion and clothed with a cell-wall. They are known as sper- 

 matia. The result of the union of the contents of the poUinodium 

 or spermatium with those of the carpogonium is a fructification 

 called the ascogonmm , which is the sporophyte of ohe fungus. 



In the simplest case, which is that of Ereniascus, two hyphae 

 coil round each other. These correspond to the carpogonium 

 and the poUinodium respectively. Their contents are said to 

 fuse, and as the result a large globular body is produced at the 

 apes of the coil, the contents of which divide into eight spores. 



In Eurotinm Aspergillus {fig. 838) a Kttle more difference 

 is found between the two hyphae. The female forms a coil, and 

 from the base of it the poUmodium arises. It becomes closely 

 adpressed to the carpogonium, and fusion of the contents of the 

 two is said to occur. Prom the base of the carpogonial filament 

 other filaments arise which grow round and envelop it. The 

 coiled carpogonium becomes septated, and from each segment a 

 little protrusion arises which enlarges and becomes an ascus and 

 forms in its interior eight spores. The investment becomes 

 also septated, and forms a thick wall to the whole body. Prom its 

 cells ingrowths arise which gradually fiU up the spaces between 

 the coils of the carpogonium, forming a solid mass of pseudo- 

 parenchyma. The body so formed is then kno%vn as the ascogo- 

 nium or ascocarp. From the fact that it remains closed and pro- 

 duces its spores internally, it is sometimes caUedacfeisfoi/iecmrre. 



The fungus Collema, which is generaUy found in symbiotic 

 relation with an Alga, may be taken as an illustration of another 

 type. The female organ is a septated coiled filament embedded 

 a little below the surface of the organism (fig. 835). Its upper 

 end is prolonged into a tapering filament, the trichogyne, which 

 projects above the surface. A spermatium liberated from the 

 spermogonium is floated passively to the trichogyne and becomes 

 attached to it. The waUs deUquesce at the point of contact, and 

 fusion of the contents takes place. The trichogyne then withers 

 and the carpogonium develops and pushes its way to the surface, 

 where it expands into a, flattened disc which is known as an 



G 2 



