219 



material from Mt. Tacoma " C. nitidiscolay This ma- 

 terial bears espinulose apothecia which would seem to 

 ally it with C. islandica rather than with C. tenuifolia, 

 and as its range would also suggest, though the plants 

 have narrow rather than expanded laciniae. It is evi- 

 dently a modification as Mr. Merrill called it, caused by 

 the corticoline substrata, a more or less accidental result 

 of environment* as the following field note on one of 

 Prof. Fink's labels goes to prove: "Collected specimens 

 on branches two or three feet from the ground and about 

 the trees at Glacier & Loggan and have a number of 

 interesting transitional forms which convince me that this 

 (Cetraria "nidiuscula" Merrill) " (note change of spelling) 

 is not a good species." All these specimens show spinu- 

 lose margins to some degree and none of them sorediate 

 margins. The one plant from Central Point, Ore., 

 collected by Mrs. Ashworth referred to by Mr. Merrill is 

 membranaceous rather than "cartilagineous," is entirely 

 espinulose, with sorediate margins, and represents typical 

 Platysma saepincola (Ehrh.) Nyl., with a dorsiventral 

 thallus and numerous rhizinae. Mr. Merrill's description 

 is therefore composite and the words "or not, in the later 

 case sometimes white sorediate" should be struck out. 

 Further material of this interesting modification may 

 prove to argue its acceptance as a variety or even species. 



Cetraria tenuifolia (Retz.) comb. nov. 

 Synonymy: Lichen islandicus /3 tenuifolius Retz., Fl. Scand. 

 prod. 227. 1779. 

 Cetraria islandica 7 crispa Ach., Lich. Univ. 513. 18 10. 

 Cetraria islandica a vulgaris f angustifolia Kremplhbr., Lich. 

 Fl. Bayerns, Denkschr. k. bay. bot. Gesell. Regens. 4: 

 121. 1861. 

 Type: In the Retzius herbarium, Botaniska Institutionen, 

 Lund, Sweden. 



* See such for Umbilicaria pustulata var. papulosa Tuck., Merr., Bryol. 9: 3. 

 1906, and Howe, ibid. 16: pi. 3. f. i. 1913. 

 t littoral examples. 



