PAPERS GIVING RUSTS OF NORTH AMERICA. 233 



the spores. Finally these having fallen out Peziza-form cavities 

 are left in the leaf. 



Represented by half of a leaf, nearly 4.5 cm. broad, mounted, 

 which is thickly covered with uredinia, and by an empty packet 

 labelled "^cidium Pyrolatum LvS in P. rotundifol Torr." 



The rust is the uredinial stage of Melampsoropsis Pyrolce (DC.) 

 Arth. (Chrysomyxa Pyrolce Rostr.), but was naturally mistaken for 

 an ^cidium by Schweinitz, as it possesses catenulate spores. The 

 host may have been P. idiginosa Torr., rather than P. rotundifolia 

 L. The name Mcidium {Caoma) pyrolatum is used by Schweinitz 

 on page 309 in the same work. 



*2894. 84. C. A. Myricatum, L.v.S., on leaves and especially on petioles of 

 Myrica cerifera, communicated to me from New York by my 

 friend Dr. Torrey. 

 C. spots on strongly sw^ollen petioles, dark purple, black where dry, 

 and out of the spots project the dense pseudoperidia, rather 

 large, widely open, brown, filled with yellowish spores. 



Represented by a mounted specimen, consisting of a terminal 

 portion of stem, 2 cm. long, with four leaves attached, three being 

 somewhat over 4 cm. long and 18 mm. wide, and with an abundance 

 of secia on the hyertrophied terminal bud, 2.5 cm. long, and by an 

 original packet containing 3 cm. of stem with four leaves attached 

 but without aecia, which is labelled on the inside " ^cidium Myricse 

 on Myrica cerifera L," and on the outside " ^cidium Myricatum 

 LvS in Myr. cerifera Torrey." 



This is the aecial form of Gymno sporangium myricatum (Schw.) 

 Fromme (G. Ellisii FarL), as proven by cultures, the telia of which 

 occur on Chamcccyparis thyoides (L.) B. S. P. The name is changed 

 to JEcidium (Cccoma) myricatum on page 309 of the same work. 



*289S. 85. C. A. Osmundatum, L.v.S., found on the fronds of Osmunda 

 spectabilis and communicated by Torrey, but in drying so de- 

 stroyed, that it is not possible correctly to describe it : the species 

 nevertheless evidently distinct: spores ferruginous. 



Represented by a narrowly triangular, lateral part of frond, 2.5 

 cm. long, blackish purple, mounted, and by an empty packet labelled 

 "^cid? Osmundatum in O. spectab Torrey." Schweinitz used the 



