PHTSCIA.] 



295 



somewhat prominent, yellowish or blackish ; sterigmata very rarely 

 subsimple. 



The species of this genus are diverse in habit, some being everniiform, 

 a few subplacodioid ; but the larger number are parmelioid. They also 

 vary somewhat in the structure of the cortical layer, the form of the 

 spores, and the spermatia." They agree, however, in what is more essential, 

 the lecaiiorine apothecia. The colour of the thallus, here closely connected 

 with differences in the fructification, enables us to arrange them under 

 two sections, which are almost entitled to be regarded as subgenera. 



A. FLAVESCENTES. Thallus yellowish. Apothecia concolorous; 

 spores polari-bilocular (the loculi usually connected by a 

 thin tube), colour- 

 less. Spermogones 

 yellowish, with sper- 

 raatia oblongo-ellip- 

 soid. Xantlwrin Fr. 

 PI. Horn. (1825) p. 243 

 pro parte. 



1. P. flavicans DC. Fl. 



Fr. ii. (1805) p. 189. 

 Thallus subfruticuloso-fila- 

 mentose, cppspitose, very 

 much and intricately 

 branched, yellow or orange- 

 yellow; beneath concolorous 

 or subconcolorous, subcana- 

 liculate; branches somewhat 

 rounded, slender, attenuate, 

 furcellate at the apices 



(K^^CaCr). Apo- Fig . 52. 



thecia lateral, small or Physcia parietina, De Not. a. Vertical section 



moderate, plane, orange- of thallus, x 200. b. Theca and paraph j sis, 



coloured, the margin thin, * 3 ?- '^pores *"& fl ? m the livin * 

 ', , plant), X 500. a. Section of sperinoeone, 



subcrenulate ; spores some- 3a ' e> Jointed ^erigmata and I spermatia, 

 times Simple, 0,012-18 x 500. /. Spores of P. ciliaris DC. X 500. 

 mm. long, 0,007-11 mm. 



thick. Mudd, Man. p. 112, t. ii. f. 33 ; Cromb. Lich. Brit, 

 p. 37 ; Leight. Lich. Fl. p. 141, ed. 3, p. 130. Parmelia flavicans 

 Tayl. in Mack. Fl. Hib. ii. p. 147. Borrera flavicans Hook. Fl. 

 Scot. ii. p. 57 ; Sin. Eng. Fl. v. p. 224. Lichen flavicans Sw. Fl. 

 Ind. Occid. iii. (1788) p. 1908 ; Eng. Bot. t. 2113. Borrera Iceta 

 Gray, Nat. Arr. i. p. 435. Lichen vulpinus (non Linn.) Huds. Fl. 

 Angl. p. 462 ; Lightf. Fl. Scot. ii. p. 896 ; With. Arr. ed. 3, iv. 

 p. 49. Usnea capillacea citrina, fruticuli specie Dill. Muse. 73, 

 t. 13. f. 16. Lichenoides quod Muscus aureits tenuissimus Dill, in 

 Ray Syn. p. 65, n. S.Brit. Exs. : Leight, n. 169 ; Mudd, n. 84 ; 

 Larb. Caesar, n. 21 ; Cromb. n. 48. 

 A beautiful plant, easily recognized by the somewhat elongate orange- 



