158 Scientific Proceedings, Royal Dublin Society. 



description in " Sylloge Fungorum " (i., p. 435), and of which a 

 figure appears in Saccardo's " Fungi Italici," t. 432 : — 



" Peritheciis dense gregariis peridermio tectis, globosis, brevis- 

 sime papillatis atris, intus candidis, ascis clavatis, rotundatis, crasse 

 tunicatis, breve stipitatis, paraphysatis, octosporis ; sporidiis, disti- 

 chis, ovoideo-oblongis, 30-40 x 6-8 fx, granulosis, guttalatisve 

 hyalinis. 



"Hab. — In ramis eorticatis Pruni, Salicis, Aim, Corni . . . Posse, 

 &c, in Italia bor., Gallia, Sibirica Asiatica, Amer. Austr." 



Physalospora is a member of the Spheeriacese, a group of 

 Pyrenomycete Ascomycetes, and characterised, amongst other 

 features, by the clustered or aggregate character of its perithecia, 

 as its name indicates. "While the Tetradia conidia probably serve 

 for the propagation of the canker-pest during the growing season, 

 the perithecia of Physalospora gregaria represent the resting stage. 



In the following spring the ascospores, escaping from the asci 

 and perithecia, germinate, no doubt, and attack the shoots of the 

 willow as they sprout. I have, as yet, no evidence to enable me 

 to say whether the ascospores or conidia can bore into the host 

 through uninjured skin, or if they have their way prepared by a 

 wound caused by insects, by rubbing together of rods in wind, &c. 



The third form of fruiting-body occurring in the same canker as 

 the Physalospora perithecia is shown in Plate XIII., fig. 5, and eon- 

 tains bodies of peculiar character. The hyphse in the pycnidium 

 arise at any point on its inner wall, branch and produce colourless, 

 bisporous, fusiform conidia, in size (12 x 4*5 /x) and in structure 

 comparable to the bisporous conidia of Diplodina salicis, Westen- 

 dorp. Very often these bodies are intercalary, occurring in the 

 course of the branching hyphse (Plate XIII., fig. 6). At first sight 

 they suggest the genus Dendrophoma, one of the Fungi Imper- 

 fecta in which the conidia are simple colourless spores, as in 

 Phoma, but differing from it in that they are formed on branch- 

 ing, not simple conidiophores. In Dendrophoma the conidiophore 

 branches are also in whorls and the conidia terminal. To include 

 the pycnidium (0*16 x 0'14 mm.) I have just described in Dendro- 

 phoma would need an extension of the characters of the genus ; 

 and as the conidia are larger than the Tetradia ones, I propose 

 for this kind of pycnidium the provisional name Macrodendrophoma 

 salicicola. 



