29 



Common on oaks across the continent. A very variable species 

 as here recognized. If it seemed possible it would be much more 

 satisfactory to distribute it under several specific names, some of which 

 are already in use. Often the form on a certain host species is suf- 

 ficiently distinct when considered by itself to merit this treatment 

 For example the type on Quercus rubra known as M. extenm, C. & 

 P., is everywhere on this host sufficiently alike to be easily recognized : 

 but, upon examining- specimens even from the same localities on allied 

 oaks, it soon becomes impossible to find dividing bounds between this 

 form and others which at first sight are very different, like that called 

 M. abbreviates, Peck on Que?*cus imbricaria, etc. It must also be 

 acknowledged that it is well nigh impossible to distinguish some forms 

 referred to M. Alni from certain specimens placed under M. quereina, 

 except by reference to the host plants. Usually however the latter 

 differs from the former by longer, commonly more numerous appen- 

 dages and larger sporidia. The perithecia also average larger. 



M. calocladophora, Atkinson, in Journ. Elisha Mitchell Soc. YH, 

 p. 13. 



Microsphceva densissima, (Schw.) Journ. Myeol. I, p. 101. 



Ilypophyllous. Mycelium, thin and diffuse or in dense, orbicular 

 spots. Perithecia black, at length depressed in the center, walls 

 thick, reticulations rather distinct, 100-140 /i; appendages not nu- 

 merous, about 7-12, subhyaline, 1-2 times diameter of the perithecium. 

 2-8 times dichotomously branched, or the axis continuous, bearing 

 two or more sets of opposite branches and the lowermost of these some- 

 times showing the same axial elongation; tips strongly incurved. Asci 

 4-6. Sporidia granular and nucleate, 6-8, 20-25 /i in length. 



On Quercus aquatica, Q. laurifolia, Florida (Martin), South Car- 

 olina and Alabama (Atkinson). 



This species is especially distinguished by the peculiar branching 

 of some of the appendages first described by Ellis and Martin (Jour- 

 nal of Mycology I, p. 101), but referred to M. densissima, (Schw.) 

 It cannot now be positively ascertained to what Schweinitz applied 

 this name, but his plant was collected at Bethlehem, Pa., upon oak 

 leaves, species not given. This is a strong evidence against his speci- 

 men, belonging to the present species. In Cooke and Peck's Erysi- 

 pliei of the United States (1872), M. densissi?na, (Schw.) was identi- 

 fied with a specimen on Quercus tinctoria in New York. This was 

 presumably correct but if so our present species is certainly distinct, 

 as it differs conspicuously from the New York specimens. There can 

 however be no doubt that the description in the Journal of Mycology 

 was drawn from specimens belonging to this newly named spec 

 (The specimen in Ell. N. A. F. 1238 is Atkinson's new species.) 



M. erineophila, Peck, Bull. Torr. Bot. Club. X, p. 75. 



Mycelium thin. Perithecia 90-100 ^, fragile, dark, opake, rerir- 



