150 University of California Pnhlieations . [botany 



fore conclude from all evidence obtainable that the algal portion 

 of the composite is Viva Galifornica Wille. Thus far no material 

 has been examined that is not completely penetrated by the 

 mycelium, and bearing perithecia. This fact makes it seem 

 probable that the fungus spores germinate and enter the tissues 

 of the young Ulva when it is first germinating from the spore 

 and they continue their development together, either in a sym- 

 biotic or parasitic relation. In this way all the tissues of the 

 Ulva are entirely penetrated by the fungus, and therefore we find 

 no mature Ulvas with the mycelium just penetrating. 



The fungus forming this composite with the Ulva is quite 

 certainly a Guignardia of some kind, as it resembles Guignardia _ 

 Prasiolce (Winter)* in habit, development, and general structure. 

 It is probably a new species, as its spores differ from that spe- 

 cies both in shape and size, and likewise the asci and perithecia. 

 It is associated with the Ulva very much as Reinsch's fungus in 

 Dermatomeris and is similar in habit, but the spores are quite 

 different . 



The spores are oval, with thick walls and 10-13 /* by 3.5-7 t^, 

 while the asci are 23-40 h- by 10-13 H-. The perithecium 

 measures 364-509 /* on the outside diameter and 120-270 /^ 

 on the internal diameter. Guignardia Prasiolce (Winter) has 

 spores 12-15 /^ by 3.5-4.5 /*, and asci 53-57 h- long by 9 y- wide. 

 The perithecium is 200-220 h- wide. The spores are decidedly 

 longer, narrower, and more pointed than those in the Ulva. The 

 spores of Reinsch's Dermatomeris Georgiea are 5.5 /^ by 2.5-2.8 f^, 

 and asci 33-47 h- by 5.5^7 h-. " Sporocarp 130 /* internal and 148 /«. 

 external diameter." From the above comparison it is conclusive 

 that our fungus is a different species of Guignardia, and perhaps 

 it may be named Guignardia Ulvce, as most fitting and suggestive, 

 because of its association with that alga. 



* Lcestadia PrasiolcB'Wmier. The species must be transferred to Guignardia, since the 

 name Lasstadia is preoccupied by a genus of Compositse. 



