THE BRYOPHYTA OF ICELAND 



511 



leaf-margin is almost straiglit in outline, while in L. decipiens it is dis- 

 tinctly concavc, as in L. filamentosa. 



The variety grew abundantly on somewhat damp rocks; it is some- 

 what coarser and less branched than tlie type which it resembles ex- 

 actly in leaf-form and size of the cells. The leaf-cells in this form are 

 so iiighly thiclvened and porous that the walls almost appear like a 

 string of beads and are often i)roader than the cell-space. 



Fig. 13. ((. Leiives ol' Lesciiræa Breidleri (,x 20 j: b. leaves ol' L. i-adicosu (X 20): 

 c. leaves of L. decipiens (X 20); d. leaves of L. decipiens v. crassirete (X 20); e, leaf- 

 cells of L. decipiens (X 320): f. leaf-cells of /.. decipiens v. crassirete (X 320). 



225. Lescuræa radicosa (Mitt.) Hagen. 



Lcsciiræa riyescens (;Wils.~) Br. eur.; Pseiidoleskea radicosa (Mitt.) Lindb. 



Ptychodinm Pfundtneri Limpr. 



N. Iceland: Oxnadalur, Tvera!; sterile. 



In the above locality it grew scantily on a stone by the river. 



226. Lescuræa filamentosa (Dicks.) Lindb. 

 Pseiidoleskea atrovirens (Dicks.) Br. eur. 

 Widely distributed. 



