MurrRILL: PoLyPpoORACEAE OF NorRTH AMERICA 297 
sphere have very probably been for ages widely separated by im- 
passable barriers of open sea. The principles above enunciated 
are well illustrated in the genus rl of Karsten, a discussion 
of which follows. 
ELFvinGIA Karsten, Findlands Basidsv. 333. 1889 
This genus was described by Karsten as follows : 
‘* Hatten bekladd med en spréd, skorpartad hud, glatt. Cystiderna foga anmark- 
ningsvirda. Basiderna n. klotrunda, 4-sporiga. Sporerna Aggrunda, virtfulla, gul- 
brunaktiga.’’ 
The only representative of the genus in Finland, according to 
Karsten, is Elfvingia applanata (Pers.) Karst., a species first de- 
scribed as Boletus Lipsiensis by Batsch (Elench. Fung. 2: 183- 
185. pl. 25. Fig. 130. a, 6. 1786), then as Boletus applanatus by 
Persoon (Obs. Myc. 2: 2. 1799), and later as Polyporus meris- 
moides by Corda (Sturm, Deutschl. Flora, 3: 139-142. pl. 63. 
1837). Its close relationship to P. fomentarius L. may be judged 
from the fact that Persoon in his Synopsis treats it as a variety of 
the latter plant, although he had described it as a distinct spe- 
cies only two years before. In the present treatment of the genus 
Elfvingia, E. Lipsiensis (Batsch) will not appear, since it does not 
occur in America, its place being taken by &. megaloma (Lév.). 
Synopsis of the North American Species 
1. Context ferruginous, spores hyaline, pileus usually ungulate. re 
Context darker, fulvous to chocolate-brown, spores yellowish-brown, pileus usually 
applanate. 3. 
2. Pileus exactly ungulate, pores 3 to a mm., growing in temperate regions south to 
Carolina. 1. £. fomentaria. 
Pileus compressed ungulate, pores 5 to a mm., growing in tropical America and the 
gulf states. 2. £. fasciata, 
3. Hymenophore annual, persisting above later growths; pileus reniform, margin thin, 
spores dark brown, roughly echinulate, 8-9 « 7. 3. £. reniformis. 
Hymenophore truly perennial, tubes stratified, spores smooth or nearly so. 4. 
4. Crust white, becoming brown, not separating, spores smooth, 8-9 < 5 u, growing 
in temperate regions. 4. £. megaloma, 
Crust brown, context floccose, softer, spores smooth or slightly echinulate, growing 
in tropical America. 5. 
5. Pileus thick, crust smooth and very hard, hymenium plane, margin truncate, very 
smooth, often laccate, context very thin, spores smooth or slightly verrucose, 
7-9 X 5-6. 5. &. tornata. 
Pileus thin, crust radially wrinkled, thinner, hymenium concave, margin undulate, 
never laccate, spores smooth, 8 x § yu. 6, Z£. Lionetiz, 
