Arthur and Kern: Peridermium 431 



W. C. Blasdale & M A. Howe. Known only from the type 

 locality, although not an inconspicuous species. 



22. Peridermium Holwayi Sydow, Ann. Myc. i : 19. 1903 



0. Pycnia chiefly hypophyllous, rather numerous, scattered, 

 inconspicuous, scarcely arising above the surface of the epidermis, 

 honey-yellow becoming brown, subepidermal, usually destructive 

 to the epidermal cells above, large, 145-160 jx in diameter. 



1. Aecia from a limited mycelium, amphigenous, scattered on 

 yellow areas occupying part or all of a leaf, slightly tongue-like 

 or flattened-cylindrical, 0.2-0.4 mm. across by 0.3-0.6 mm. long, 

 low, 0.4-0.8 mm. high ; peridium colorless, delicate, dehiscence 

 irregular, margin becoming lacerate, cells overlapping, walls not 

 striate, outer thin, inner considerably thickened, and strongly 

 tuberculate ; aeciospores broadly ellipsoid, 15-18 by 18-24 /i, 

 wall colorless, thin, about 1 fx y evenly and finely verrucose. 



On Pseudotsuga mucronata (Raf.) Sudw. {Pseudotsuga Douglasii 



Carr., Abies Douglasii Lindl.), Glacier, British Columbia, August 



11, 190 1, E. IV. D. Hokvay. Known only from the type locality. 



23. Peridermium conorum-Piceae (Reess) nom. nov. 



Aecidium conorum-Piceae Reess, Abh. Nat. Ges. Halle 11 : (54). 



1869. 

 Peridermium conorum Thuem. Mitth. Forstl. Vers. Oest. 2: 313 



(17). 1880. 

 Peridermium Engelmanni Thuem. Mitth. Forstl. Vers. Oest. 2 : 



314 (18). 1880. 

 Aecidium Engelmanni Dietel, in Engler & Prantl, Pflanzenfam. 



I 1 ** : 79. 1897. 



0. Pycnia episquamous, numerous, subepidermal, fiat, form- 

 ing continuous layers, 600-900 fit broad, 50-100 /* high, incon- 

 spicuous, not noticeably elevating the surface. 



1. Aecia chiefly episquamous, subepidermal, forming bullate 

 swellings, irregularly round, large, crowded and often confluent, 

 finally rupturing the epidermis, very pulverulent ; peridium irregu- 

 larly convex, soon dropping away, cells broadly ellipsoid or glo- 

 boid, loosely united, coarsely tuberculate, resembling the spores ; 

 aeciospores broadly elliptical or obovoid, large, variable in size, 

 20-27 by 25-40/^, wall colorless, thick, 4-5 /A half formed by 

 the large deciduous tubercles, which are rather crowded, broad, 

 3-4 jx y and depressed. 



