422 Arthur and Kerx : Peridefmium 



numerous, scattered, individual sori elongate and sometimes tor- 

 tuous, 1-2 by 3-9 mm., distinct or rarely confluent, pale-yellow, 

 bladdery, low, scarcely exserted above the bark ; peridia circum- 

 scissile, soon falling away, about two cells thick, outer surface in- 

 folded and verrucose, inner more coarsely verrucose, cells round- 

 ish or irregular, walls very thick, radially striate, lumen small ; 

 aeciospores obovate or ellipsoid, 15-24 by 24-33 fa vva ^ colorless, 

 3-5 it thick, uniform, coarsely verrucose, usually with smooth area 

 at base, often extending up one side, tubercles about I fi long, 

 tardily deciduous. 



On branches of Pinus Taeda L., Auburn, Alabama, April, 

 1896, L. M. Undenvood (type) ; Auburn, Alabama, no date, F % S. 

 Earle (specimen at Miss. Valley Lab., St. Louis) ; Lake City, 

 Florida, March, 1895, P. H. Rolfs ; Gainesville, Florida, February, 

 12, 1906, P. H. Rolfs. 



On branches of Pinus palustris Mill., Cleveland, Texas, no 

 date, Perley Spaulding (specimen in herbarium Missouri Bot. 

 Garden, St. Louis); Lake City, Florida, June, 1906, P. H. Rolfs. 



On branches of Pinus sp., Georgia, no date, H. W. Ravenel 

 (specimen in herbarium N. Y. Bot. Garden) ; Cairo, Georgia, 

 March 26, 1904, P. J. G Gara (specimen in herbarium U. S. 

 Dept. Agric). 



The spindle-shaped gall is very characteristic of this species, 

 which rarely shows an abrupt change from the healthy tissue to 

 the hypertrophied area, as in other species. 



13. Peridermium mexicanum sp. nov. 



0. Pycnia unknown. 



1. Aecia caulicolous, forming irregular, globoid, gall-like ex- 

 crescences, 3-7 cm. across, often on small branches, arranged in 

 tortuous lines or cerebroid, pale-yellow fading to white, bladdery, 

 not much exserted above the bark ; peridia colorless, circumscis- 

 sile, soon falling away in flakes or sheets, about 2 cells thick, outer 

 surface somewhat irregularly roughened, inner surface more 

 noticeably roughened, cells roundish or irregularly compressed, 

 walls thick, with radial striations, which may on exposed sur- 

 faces separate the wall into tubercle-like processes, lumen moder- 

 ately small ; aeciospores ellipsoid or obovate, 13-22 by 23-33 ft, 

 wall colorless, 2.3 fi thick, very coarsely verrucose, sometimes 

 with a smooth area showing at base and extending up one side, 

 slightly thicker, 3-4 /i, tubercles somewhat deciduous. 



