Arthur and Kern: Peridermium 433 



and is frequently collected in the New England states and along 

 the Pacific coast, which makes it reasonably certain that the aecial 

 form will be found eventually within the same regions. 



A peculiarity of this Peridermium \s the absence of pycnia. So 

 far none have been found in authentic specimens, which makes one 

 think that they may never occur. Very low, inconspicuous pycnia 

 are to be found in a closely related species, which often passes under 

 the same name (see Sydow, Ured. 8p6 and Vestergren, Micr. rar. 

 sel. 754), a form also undetected in America. 



25. Peridermium ornamentale Arth. Bull. Torrey 



Club 28 : 665. 1901 



Aecidium ornamentale Farl. (non Kalchbr. 1875) Bibl. Index 1: 

 71. 1905. 



0. Pycnia amphigenous, numerous, flat, often confluent, incon- 

 spicuous, subcuticular, in section broad and low, slightly convex 

 or even a little conical, 150-210 fx broad, 25-35 P high. 



1. Aecia from a limited mycelium, hypophyllous in two rows 

 on yellowish spots occupying part or all of the leaf, large, 1-2 

 mm. high, somewhat flattened laterally; peridium bladdery, color- 

 less, rupturing irregularly, cells overlapping, rather large, outer 

 wall smooth, rather thin, 2 ft, inner wall thicker, 3-5 fi, moderately 

 verrucose ; aeciospores with cylindrical intercalary cells, 3-4 by 

 5-8 //, spores broadly ellipsoid, 13-18 by 20-29 /i, wall colorless, 

 thin, 1 — 1 . 5 /^, closely and finely verrucose ; contents orange-red, 

 fading to pale-yellow. 



On Abies lasiocarpa (Hook.) Nutt, mountains of Skamania 

 County, Washington, August II, 1886, W. A 7 ". Suksdorf 296 ; Mt. 

 Paddo, Washington, 6000 ft. alt, September 4, 1900, W. N. Suks- 

 dorf 588 (type collection) ; Laggan, Alberta, Canada, 6500 ft. alt., 

 September 20, 1905, E. W. D. Hohvay. 



26. Peridermium Peckii Thuem. Mitth. Forstl. Vers. 



Oest. 2: 320 (24). 1880 

 Aecidium Peckii Dietel, in Engler & Prantl, Pflanzenfam. I 1 ** : 78. 



1897. 



O. Pycnia hypophyllous, numerous, scattered, inconspicuous, 

 subcuticular, extending considerably into the walls of the epi- 

 dermal cells, in section broad and low, slightly convex or even a 

 little conoidal, small, 65-125 11 broad, 20-26 ;i high. 



