HEMIBASIDIOMYCETES 329 



matia are minute, subglobose, or flask-shaped structures, 

 either immersed in the epidermis, or only covered by the 

 cuticle, through which the open neck protrudes. The 

 spermatia, produced at the tips of delicate hyphae spring- 

 ing from the basal portion of the inner surface of the 

 spermogonium, are very minute, hyaline, and one-celled. 

 The significance of spermogonia and spermatia is not 

 clearly understood. In certain instances spermatia have 

 been induced to germinate. Cornu did this by placing the 

 spermatia in a weak solution of sugar in water. Notwith- 

 standing such power of germination, spermatia appear to 

 be quite incapable of producing a mycelium, or of giving 

 origin to a new phase of the fungus. The most general 

 opinion respecting spermatia is that which regards them 

 as effete male organs, equivalent to the organs present in 

 Collema and other Lichens. If this view is correct, it 

 implies the presence at some past period of a trichogyne, 

 a view advocated by Blackman, as already described. In 

 many species the production of spermogonia has com- 

 pletely ceased, but when present they always accompany 

 the aecidium stage. 



The aecidiospores are produced in chains within a 

 special structure called an aecidium or pseudoperidium. 

 Aecidia are popularly known as 'cluster-cups.' When 

 the peridium is short and opens in a stellate manner with 

 the lobes recurved, it once constituted the genus Aecidium. 

 When the peridium is long and cylindrical, it constituted 

 the old genus Itoestelia. The aecidiospores are one-celled, 

 with a colourless cell-wall, and usually bright orange con- 

 tents. The pseudoperidium sometimes opens by a pore, 

 but more frequently becomes torn irregularly at the apex ; 

 the torn edge splits at intervals, and the segments become 



