PHYSCIA.] 



rntaciEi. 



295 



somewhat prominent, yellowish or hlackish ; stcrigmata very rarely 

 subsimple. 



The species of tliis frenus arc diverse in liabit, some hein^' everniiform, 

 a few subplacodioid ; but the lar^/er number are parinelioid. They also 

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

 spores, and the spermatia. They a<n'ee, however, in what is more essential, 

 the lecanorine 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. FLAYESCENTES.— Thallus yellowish. Apothecia concolorous; 

 spores polari-bilocular (the lociili usually connected by a 

 thin tube), colour- 

 less. Spcrmogoncs 

 j-ellowish, with sper- 

 matia oblongo-cllip- 

 soid. — XantJioria ¥r, 

 PI. Hom. (1825) p. 243 

 pro parte. 



1. P. flavicans DC. Fl. 

 Fr. ii. (1805) p. 189.— 

 Thallus subfruticuloso-fila- 

 mentose, ca-spitose, very 

 much and intricately 

 branched, yellow or orange- 

 yellow; beneath concolorous 

 or subconcolorous, subcana- 

 liculate; branches somewhat 

 rounded, slender, attenuate, 

 furcellate at the apices 

 ^j^+purplish^ CaClI). Apo- 

 thecia lateral, small 

 moderate, plane, 

 coloured, the margin thin, 

 subcrenulate ; spores some- 

 times simple, 0,012-18 

 mm. long, 0,007-11 mm. 

 thick.— Mudd, Man. ]). 112, t. ii. f. 33 ; Cromb. Lich. Brit, 

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

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

 Scot. ii. p. 57 ; Sm. Eng. Fl. v. p. 224. Lichen jlavicans Sw. Fl. 

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

 Grav, Xat. Arr. i. p. 435. Lichen vulpinus (non Linn.) Huds. Fl. 

 Angl. p. 462 ; Lightf. Fl. Scot. ii. p. 896 ; ^'ith. Arr. ed. 3, iv. 

 p. 49. Usnea capiUacea ciirina, fruticuli sjiccie Dill. Muse. 73, 

 t. 13. f. 16. Lichenoides quod Muscus aureus temiissimus Dill, iu 

 Hay Syn. p. 65, n. 8.— Brit. Evs. : Leight. n. 169 ; Mudd, n. 84 ; 

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



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



Fig. 52. 

 or Physcia parietina, De Xot. — a. Vertical section 

 oran""e- of thalUis, X 200. h. Thecaand paraphysis, 

 X 350. c. Spores (mostly from the lirlng 

 plant), X 500. d. Section of speriuogone. 

 X oO. c. Jointed stericrmata and spermatia, 

 X 500. /. Spores of P. ciHaris DC. X 500. 



