418 Arthur and Kern : Peridermium 



0.5-1.5 mm. long, by I— 1.8 mm. high, rupturing irregularly; 

 peridium colorless, moderately firm, cells somewhat overlapping, 

 30-40 fj. long, walls transversely striate, inner moderately verru- 

 cose, thick, 6-9 /i, outer less rough and thinner, 4-6// ; aeciospores 

 ellipsoid, 18-24 by 23-39 /A wa ^ colorless, closely and evenly 

 verrucose with large deciduous tubercles, 3.5 fx thick. 



On leaves of Pinus Jilifolia Lindl., mountains above Oaxaca, 

 Mexico, May 28, 1894, C. G. Pringle (type); Topalpa, state of 

 Jalisco, Mexico, June 10, 1892, collector unknown (specimens in 

 herbarium of N. Y. Bot. Garden). 



8. Peridermium filamentosum Peck, Bot. Gaz. 



7 : 56. 1882 



Aecidium filamentosum Farl. Bibl. Index I : 44. 1905. 



0. Pycnia unknown. 



1. Aecia caulicolous, not producing noticeable swellings, scat- 

 tered, cylindrical, 4-7 mm. high by 1-2 mm. wide, pale-yellow 

 or white ; peridium rupturing laterally in longitudinal lines, rather 

 firm, scarcely more than 1 cell thick at the sides, becoming thicker 

 above where it extends downward into numerous concolorous, 

 filament-like processes, 70— 100 ft in diameter, passing through the 

 spore-mass from apex to base of the aecium, peridial cells linear- 

 oblong, 1 5-23 by 5 5-80 fi y pointed at one or both ends, placed 

 longitudinally, walls 4— 6 /z thick, inner rather coarsely verrucose, 

 outer somewhat smoother ; aeciospores oblong, obovate-oblong or 

 rarely ellipsoid, 13-21 by 27-31 /i, wall colorless, uniformly thick, 

 2. 5—3. 5 /^. moderately verrucose, with a smooth area at base often 

 extending up one side. 



On Finns ponderosa Dougl., Santa Rita Mountains, Arizona, 

 July 13, 188 1, C. G. Pringle. This remarkable and interesting 

 species of Peridermium has been collected but once, although an 

 interval of a quarter of a century has passed, and the fungus is a 

 conspicuous one. Mr. C. H. Peck in his account in the Botanical 

 Gazette, gave an excellent characterization, and very properly laid 

 stress on the presence of longitudinal filaments, and on the slitting 

 of the peridium. The filaments are easily seen, even without a 

 hand-lens, and extend from the dome of the aecium to its floor, 

 and are sufficiently numerous to keep the spores from easily falling 

 away, even after the rather fragile peridium has partially disap- 

 peared. The apex or dome of the peridium, as in other forms on 

 the branches of pine, is more than one cell thick, but the long 



