762 Proceedings of the Royal Irish Academy. 



association of the Cephaleuros of Kunze with the lichen Strigula 

 had been described long ago by Montagne, who regarded the alga as 

 a degenerate form of the lichen. 



Berkeley in his remarks on the tea blight, indicates that he had 

 observed a similar connection ; while Fries, Nylander, and Saccardo 

 have commented on the peculiar variability of the lichen Strigula and 

 its frequent association with other epiphyllous organisms. 



In the case of Phycopeltis expansa we have an interesting example 

 of the connection of apeltoid alga with both fungus hyphse and lichen- 

 forming hyphee. 



When examined with a lens, the greater part of the Phycopeltis 

 appears to give rise to a number of slender brown hairs, the arrange- 

 ment of which often renders the growth-zones of the alga very 

 distinct. On careful examination it is found that these hairs do not 

 rise from the cells of the disc but apparently from the radial walls. 

 They do not in fact belong to the alga at all, but rise from fungoid 

 hyphse, which run between the adjacent cell-rows of the disc. These 

 hypha3 are sometimes colourless and extremely fine so as to be almost 

 invisible between the cell- walls ; but in older parts they are brown, 

 repeatedly septate and often moniliform. In this stage they often 

 give off lateral outgrowths following the transverse cell-walls and 

 anastomosing with the next radial hypha. The aerial hyphae are 

 always brown, but with a truncated hyaline extremity from which, 

 in a few cases, I have observed a colourless fusiform sporidium in 

 course of abstriction. 



Both Cunningham and Marshall Ward observed similar brown 

 hyphae in association with ' Mycoidea.' The latter author attributed 

 to them the formation of the lichen Strigula, though his figures do not 

 seem to support this view. 



In that described by Cunningham, the lichen-forming hyphae were 

 quite different from the brown ones ; and in that now under conside- 

 ration I cannot discover that the brown fungus has any efi'ect on the 

 algal growth. 



There occur also in parts brown hemispherical gelatinous masses 

 enclosing radiating moniliform filaments. Similar bodies were also 

 observed by the writers just mentioned, but I believe their connection 

 with any of the other organisms was not shown. I am of opinion 

 that they are quite separate plants, unconnected with the hyphae ; 

 not only because no connection is traceable but also because they 

 occur on the pinnae of Asplenium falcatum, where no hyphae are to be 

 found. 



