297 Murrill: Polyporaceae of North America 



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 Elfvingia 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 sprod, skorpartad hud, glatt. Cystiderna foga anmark- 

 ningsvarda. Basiderna n. klotrunda, 4-sporiga. Sporerna aggrunda, vartFulla, 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.//. 2§. Fig. I JO. a, b. 1786), then as Boletus applanatus by 

 Persoon (Obs. Myc. 2: 2. 1799), and later as Poly poms ineris- 

 moidcs by Corda (Sturm, Deutschl. Flora, 3 : 139-142./)/. 6j. 

 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 E. uiegalouia (Lev.). 



Synopsis of the Biortti American species 



1. Context ferruginous, spores hyaline, pileus usually ungulate. 2. 

 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. I. E. fometitaria. 



Pileus compressed ungulate, pores 5 to a mm., growing in tropical America and the 

 gulf states. 2. E. fasciata. 



3. Hymenophore annual, persisting above later growths ; pileus reniform, margin thin, 



spores dark brown, roughly echinulate, 8-9 X 7,w- 3- ^- reniformis. 



Hymenophore truly perennial, tubes stratified, spores smooth or nearly so. 4. 



4. Crust white, becoming brown, not separating, spores smooth, 8-9 X 5 ,"' growing 



in temperate regions. 4- ^- megaloma. 



Cru.st 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, 

 7-9X5-6". 5- E. turnata. 



Pileus thin, crust radially wrinkled, thinner, hymenium concave, margin undulate, 

 never laccate, spores smooth, 8X5/"- (y. E. Lioneth. 



