Ferdinandsen & Winge: Phyllachorella 103 



to the Dothideales. Its clypeus-like stromata refer it to the 

 Phyllachoraceae 1 (Fig. 2). The curious substratum makes im- 

 possible a direct parallel between the position of this fungus in 

 the tissue and that of the Phyllachoraceae, which are parasites on 

 phanerogamous plants. However, we consider that it is correct 

 to refer the fungus to the genus Phyllachorella Sydow. 



The fungus was found present on two distinct species of Sar- 

 gassum. The stromata of the fungus were usually overgrown 

 with epiphytes. A diagnosis in Latin follows : 



Phyllachorella oceanica Ferdinandsen & Winge, sp. nov. 



Stromatibus matrici tumefactae insidentibus, strato corticali 

 innatis, nunc unilocularibus, punctiformibus, nunc crustas mori- 

 formi-tuberculatas, usque ad 1 cm. latas formantibus, atris. 

 Loculis in tuberculo singulo stromatis pluribus immersis, fere 

 globosis, 500-800 fx diam., supreme strato nigref acto crasso, quod 

 saepius inter loculos plus minusve prorepit eosque interdum cin- 

 git, tectis. Stratis subjacentibus matricis hyphis fungi inter- 

 textis. Ascis late ellipsoideis, plerumque S5~77 /* X 24-32 

 sessilibus; paraphysibus nullis. Sporis octonis, distichis, asep- 

 tatis, hyalinis, multiguttulatis, plurimis 20-30 /x, X 10-13 /x, forma 

 ( ? secundum aetatem) valde varia : saepius ellipsoideis utrinque 

 late rotundatis vel truncatis, rarius fusiformibus, apicula recta 

 subcurvatave predictis. 



Species habitatione praedistincta, oceanica, caules nec non 

 vesicas duarum specierum Sargassi, sub nominibus Sarg. II et 

 Sarg. Ill descriptorum, 2 infestans, Lat. 33 0 21' N. Long., 45 0 

 20' W. mense Martio, 1914, a cl. C. H. Ostenfeld lecta. — Stromata 

 saepe Aglaophenia latecarinata et Membranipora tuberculata 

 obsessa. 



Copenhagen, Denmark. 



1 F. Theiszen and H. Sydow. Die Dothideales, Berlin, 1915. 



2 In O. Winge : The Sargasso Sea, its boundaries and vegetation. [Re- 

 port on the " Thor " Expeditions, 1908-10, in the Mediterranean and adjacent 

 seas, 1920.] 



