40 TJSNEA. 



coloured, the wide-lobed states paler beneath ; apothecia lateral, 

 middling-sized, sub-pedicellate; disk chestnut. Spores ellipsoid, 



5-7 mic. Ach. L. U. p. 442. Fr. L. E. p. 25. Tuck. Exs. 



H-*4 



n. 54. Nyl. Syn. I, p. 285. 



Trees, fertile ; and on dead wood, sterile ; Northern States, 

 Muhlenberg Catal. 1818. Arctic America, Richardson. Pacific 



Coast, Menzies. Black Hills, Nebraska, Dr. Hay den. Sper- 



matia of the present and next following species similar to those 

 of the last. Nyl. 



5. E. divaricata (L.) Ach.; thallus prostrate, or pendulous, 

 teretish or more often somewhat compressed and augulate, lacu- 

 nose-rugose, flaccid; pale-straw-coloured; the much elongated, 

 dichotomously more or less divided branches passing into fili- 

 form, acute tips ; apothecia lateral, middling-sized ; disk chest- 

 nut. Spores ellipsoid, much as in the last. Ach. L. U. p. 441. 



Fr. L. E. p. 25. Nyl. Syn. l,p. 285. 



Trees (branches of pines and firs), infertile, Rocky Moun- 

 tains (Hall), Tuckerman Calif. 1866. Mountains of Colorado, G. 

 Vasey. The thin cortical layer often breaking, and displaying 

 the soft but yet string-like medullary, in the manner of Usnea. 



V. USNEA (Dill.) Ach. 



Apothecia orbicular, peltate, sub-terminal ; disk pale, or 

 very rarely blackening ; margin radiately fibrillose. Spores 

 sub-ellipsoid, simple, colourless. Spermatia oblong, and 

 staff-shaped, a little thickened towards the base ; 0*1 sub- 

 simple sterigrnas. Thallus fruticulose, or more commonly 

 pendulous, more or less terete, or now angulate, alike on all 

 sides; glaucescent, or rarely straw-coloured; the medullary 

 layer two-fold; an exterior, cottony portion enclosing an 



interior, indurated cord. Anatomy of the thallus (of the 



second section) in Schwend. Untersuch. I. c. 2, pp. 110-144, 

 t. 1, 2. 



* Medullary cord at length discontinuous and cottony at the 

 centre ; especially below. Disk of apothecium black. 



1. U. sulphurea (Mull.) Th. Fr. ; thallus tufted, erect, terete, 

 dichotomously branched, papillate-scabrous, deeply pitted with 



