322 Howe: Preliminary notes on the genus Usnea 



never bambusaceous or papillate, it is nearly always scurfy, the main 

 filaments of the thallus often appearing white, so thickly clothed 

 are they in a furfuraceous crust This feature is so characteristic 

 and common that it may almost be used as a safe diagnostic 

 character. The fibrillation suggests artgtdata^ though the fibrils 

 are of more varying length, of a more slender nature, and are more 

 thickly beset. "^ Apothecia, so far as I know, have never been 

 observed in New England specimens. 



Usnea longissima is a species common to high altitudes, typical 

 of the Canadian zone, which, it will be seen, allows its occurrence 

 in Vermont, New Hampshire, and Maine (excluding the sea-coast 

 in the latter south of Portland). I have examined no specimens 

 collected below an altitude of 1200 feet, except from the Maine 

 coast, where latitude equals altitude and where it is rare and 

 poorly developed. Willey, a contemporary of Tuckerman, did 

 not include it in his New Bedford list, but, of late, specimens from 

 Transition regions have been erroneously determined as longissima, 



Usnea cavernosa Tuck. 



I cannot find any reference to the occurrence of this species 

 in New England other than Tuckerman's statement, ''White 

 Mountains,'* in his Synopsis of 1882 (p. 43). From this we can 

 judge it is a rare member of the genus, perhaps the rarest, that 

 occurs in these states, and that it is confined to the Canadian 

 zone. I have examined but one specimen from this area, collected 

 by Miss Cummings at Plymouth, N. H., March, 1891, and pre- 

 served in her herbarium at Wellesley College.f The pitted and 

 compressed thallus of this species is perfectly diagnostic. The 

 fibrillation suggests trichodea. 



In closing this paper it seems decidedly preposterous for me 

 to question the determinations made in this genus by Miss Clara 

 E. Cummings, and yet I am certain after a most careful study of 



epapillat 



criteria of papillate or 

 :her distinctions), and I 

 Usnea longissima Ach., 



*This is especially true of tropical and other regions of large rainfall, where it 

 becomes shaggy, 



t Another specimen (no. 114B in author's herb.) has lately been received from 

 Dr. Manton Copeland from Brunswick, Maine. 



