Arthur and Kern: Peridermium 419 



cylindrical sides are for the most part composed of a single layer 

 of cells, and these have their longer axis extending longitudinally, 

 as in foliicolous forms, instead of transversely as in other caulicolous 

 forms. This structure permits of the longitudinal rupture of the 

 peridium, which is especially notable. 



9. Peridermium stalactiforme sp. nov. 



0. Pycnia unknown. 



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

 tered, round or irregular, 0.5-1.5 by 1-2 mm., distinct or some- 

 times confluent, pale-yellow fading to white, low, not much exserted 

 above the bark ; peridium hemispherical or tortuous, rupturing 

 irregularly along the sides, about 2 cells thick, often extending 

 numerous concolorous processes from apex and from floor of the 

 aecium a short distance into the spore-mass, peridial cells roundish 

 or occasionally elongate and somewhat pointed, walls thick, striate, 

 lumen small ; aeciospores ellipsoid, 16-21 by 27-35 /i, wall color- 

 less, 2.5-3.5/^ thick, moderately verrucose, with a smooth area 

 extending from base up one side, slightly thicker on smooth side. 



On branches of Pimts Murray ana Oreg. Com., Chiquash 

 Mountains, Skamania County, Washington, July 22, 1 901, IV. N. 

 Suksdorf 64.5 (type), communicated by E. W. D. Holway. 



On branches oi Pinus Jeffreyi Oreg. Com., Little Valley, 

 Washoe County, Nevada, 2COO-2 155 m., July 24, 1902, C. F. 



Baker rjjf. 



This species does not produce noticeable enlargement of the 

 branch, in this respect being similar to Per. filamentosum, but the 

 peridium is of the usual character of the caulicolous species. In 

 the short attenuate projections from the floor and dome of the 

 aecium, one is reminded of the connecting filaments of Per. fila- 

 mentosum, with which they are homologous. 



10. Peridermium pyriforme Peck, Bull. Torrey Club 



6: 13. 1875 



Aecidium pyriforme Farl. Bibl. Index I : 78. 1905. 



0. Pycnia unknown. 



1. Aecia caulicolous, producing no or only slight swellings, 

 scattered, rounded or irregular, 1-1.5 by 1-2 mm. across, 

 rarely larger by becoming confluent, pale-yellow or white, about 

 1-1.5 mm. high; peridium bladdery, subhemispherical, rupturing 



