IICHENES 438 



SUBORDER I. GYMNOCARP1. 



Apothecia, open, discifbrm; txcipU thalline, or proper; disk ascigerous, persistent. 



TRIBE 1. PARMELIA V CEAE. 



ApotlKcia rounded, from concave becoming explanate, scutellaeform, or rarely 

 peltate; disk somewhat waxy, contained in a thalline exciple. 



SUBTRIBE 1. USNEE^AE. 



Disk open; thallus subvertical, or pendulous-sarmentose, centripetal, without 

 apparent hypothallus. 



591. USffE'A, Dillen. 



[A name derived from Arabic authors.] 



Apothecia subterminal, orbicular, peltate, radiate-ciliate, seated on 

 the medullary stratum. Thallus suffruticulose, cartilagineous, pale, 

 filiform-ramose; medulla thread-like, elastic, subdiscrete. Plant 

 suberect, or pendulous. 



l.U. barbuta, Fr. [Bearded}- Thallus terete, irregularly 

 branched, becoming annulate-cracked, glaucous ; apothecia discoid, 

 nearly immarginate, pale. We find the following Vara. 



Tar. a. florida, Fr. much branched, scabrous, sub-erect, divergent, fibrillose ; 

 apothecia large, long-rayed. 



Far. b. strigosa, Ach. small, everywhere thickly fibrillose-strigose. 



Far. c. nibiyinea, MX. small, suberect-spreading, ferruginous. 



Far. d. hirta, Fr. dwarfish, much branched, slender, hirsuto-fibrillose, often 

 pulverulent-scabrous. 



Far. e. plicata, Fr. elongated, pendulous, dichotomously branched, smooth, pale. 



Far. f. dasypoga, Fr. elongated, pendulous, sub-simple, divaricate-fibrous. 

 Hoi). Vars. a. b. e. and f. mostly on trees ; c. and d. on fences : common. 



Obs. These varieties, except a, mostly sterile with us. 



2. 17, anglllata, Ach. [Angled'] : Thallus elongated, pendul- 

 ous, flexuose, sparingly branched, angular, the angles acute, 

 scabrous ; fibres horizontal, simple, short, terete-attenuate. 

 Hob. Trunks of trees : rare. Sterile with us. 



592. EVER'WIA, Ach. ' 



[Gr. Eu. well, and Ernos, a branch; the species being much branched.] 

 Apothecia scutellaeform, marginal, seated upon the medullary layer. 

 Thallus sub-erect, terete-fruticulose, or coinpressed-foliaceous, fist- 

 ular, or containing a cottony medulla. 



t Thallus terete-JUamentous. 



1. E. jubiita, />. [Maned]: Thallus smooth, divaricate-branched, 

 dark-fuscous, sometimes paler, apices simple; apothecia innate- 

 sessile, entire, of the same color with the thallus. 



Far. b. cTialybeiformis, Ach. sub-filamentous, decumbent, apices paler, often 

 White-sorediiferous. 

 Bab. Old rails, Ac. common. Sterile. We have only the Far. 



ft Thallus compresscd-foliaceous, channelled beneath. 

 28 



