Vol.1] Reed. — Two New Ascomycetons Fungi. 157 



northern habitat. The description will be given later in the 

 paper. 



The fungns associated with the Prasiola horealis is probably 

 a different species from that collected hy Hooker and Hariot, as 

 there is considerable difference in the measnrements of both 

 the asci and ascospores. The Alaskan species has spores 

 8.5-13.5 /A by 3-4 /* and asci 25-33 /«■ by 7-14 t^, while the spores 

 of Harlot's species, according to Winter, measure 12-15 /^ by 

 3.5-4-5 /A, and the asci 53-57 /* by 9 or 10 /*. The spores of the 

 Alaskan species are shorter and thicker in proportion than 

 those of Guignardia Prasiohe (Winter), so that both tne shape 

 and size differ from Winter's species. It may be appropriately 

 named Guignardia Ala.skana, and will be described later. 



RELATION OF THE FUNGUS TO THE ALGA. 



Upon a careful examination of the Ulva-composite, the idea 

 of a symbiotic relation between the alga and fungus, similar to 

 that of the ordinary lichen, is suggested. The outer gelatinous 

 layer with the erect hyphal filaments embedded in it, the layer of 

 green algal cells beneath, which are separated from one another 

 by these upright filaments, and in the center the medullary 

 layer of compactly woven filaments surrounded by gelatin which 

 completely separates the algal cells of the upper and lower 

 surfaces of the frond, all suggest very strongly the lichen 

 structures, while the perithecia, scattered irregularly over the 

 surfaces of the road, and opening on either surface, together 

 with the structure of the perithecia, especially the parenchy- 

 matous layer and its pigmentation, are also very much like 

 certain ascomycetons lichens with heteromerous thalli. 



In texture and general superficial appearance, the fronds are 

 also very similar to some lichens. The bud-like projections of 

 the isolated cell groups which form small adventitious fronds, or 

 possibh' soredia, are likewise characteristic of lichens. 



On the other hand, the plant retains the general Ulva form 

 and structure, having the usual holdfast, stipe and ordinary 

 shaped fronds with the two layers of cells of nearly normal 



