Arthur and Kern: Peridermium 417 



0.7-1.5 mm. high, rupturing irregularly; peridium yellow fading 

 to white, fragile, cells 35-45/* long, somewhat longer than broad, 

 overlapping, walls transversely striate, inner moderately verrucose, 

 about 4-6 ;i thick, outer less rough and of about equal thickness; 

 aeciospores broadly ellipsoid or globoid, 17-22 by 22-31 //, wall 

 colorless, densely verrucose with prominent elongate papillae, 

 2 ~3-5 P thick. 



On leaves of Hnus rigida Mill., Sugar Grove, Ohio, May 17, 



1902, May, 1902 (in Kellerman, Ohio Fungi, no. 104), May, 



1903, and May 30, 1904, W. A. Kellerman; Egg Harbor, New 

 Jersey, June, 1877, /. C. Martindale (specimen in herbarium of 

 N. Y. Botanical Garden); Ironton, Ohio, May 27, 1892, Wm. C. 

 Werner (specimen in herbarium of U. S. Department of Agri- 

 culture). 



This rust, as here represented, is the aecial form of ' Coleosporium 

 Cam pecuniae (Pers.) Lev. The demonstration was carried out by 



— _ * * 



Professor Kellerman,* who, in June, 1904, successfully sowed spores 

 from the Sugar Grove station on Campanula am eric ana. This is the 

 only culture of Peridermium on pine leaves that has yet been suc- 

 cessfully made in America. The other two collections that are 

 listed agree closely in microscopic characters with the Sugar 

 Grove collection, and are listed here with much confidence. Still 

 another collection on Piuus rigida t collected at Lunenburg, Mas- 

 sachusetts, by F. L. Sargent, on July 1, 1889, possesses consid- 

 erably larger spores, but is otherwise quite similar. While it may 

 belong with this species, it is more likely to belong to one of sev- 

 eral species of Coleosporium, whose aecial forms have not yet been 

 identified. Much cultural work has been done in Europe on this 

 and related species, for which the reader is referred to Klebahn's 

 Die wirtsweckselnden Rostpilze, and Fischer's Die Uredineen der 



SchwetB* 



7. Peridermium gracile sp. nov. 



0. Pycnia amphigenous, numerous, scattered, dehiscent by a 

 longitudinal slit, 1 90-350// broad by 0.5-0.75 mm. long, low-con- 

 oidal, subcorticular, 60-75// high. 



1. Aecia amphigenous, from a limited mycelium, numerous, 

 scattered on discolored spots occupying part of a leaf, erumpent 

 from longitudinal narrow slits 0.3-0.5 mm. wide, flattened laterally, 



Jour. Myc. n : 32. 1 905 



