182 LICHENACEI. [ROCCELLA. 



34. ROCCELLA DC. Fl. Fr. ii. (1805) p. 334. Thallus sub- 

 fruticulose, usually opaque and smoothish, somewhat tough, atten- 

 uate at the apices, con- 

 colorous on both sides, 

 medullary layer dense. 

 Apothecia lateral, leci- 

 deine or irregular,naked 

 or pruinose ; hypo- 

 thecium thick, black ; 

 spores oblong or fusi- 

 form, straight or curved; 

 hy menial gelatine wine- 

 red or wine - yellow, 

 or sometimes slightly 

 bluish with iodine. 

 Spermogones lateral, 

 with acicular, curved 

 spermatia. 



The thallus is more or 

 less fruticulose from a 

 common base,and in some 

 species is of considerable 

 size. It is whitish, rarely Fig. 37. 



brownish, in colour and ^^ phycopsis Ach.-a. Section of external 

 iirm, though sometimes tion O f the thall s i lowing t h e cortical and 



from tenuity becoming - 



flaccid. The cortical and 

 gonidial systems, as ob- 

 served by Nylander, Syn. 

 i. p. 256 \cfr. Flora, 18G6, 

 p. 198), form a confluent 

 layer, the cortex, which 



is'destitute of an epithallus, consisting of medullary filaments thickened 

 towards the surface and there densely parallel, external to which are seen 

 granular element*, while internally and immediately beneath the cortex 

 are the gouidia. The apothecia are lecideine or variously deformed, often 

 as in Dirina, sometimes as in Chiodecton, with the paraphyses slender or 

 nearly moderate, and not unfrequently bifurcate. 



gonidial layers and a small exterior portion of 

 the medulla, X 200. b. Gonidia, x350. c. Ver- 

 tical section of an apothecium, X30. d. Theca 

 and paraphysis, X350. e. Spores, XoOO. /. 

 Vertical section of a spennogone, X 30. g. 

 Sterigmata and spermatia, X 500, 



1. R. phycopsis Ach. Lich. TJniv. (1810) p. 440. Thallus 

 rounded or slightly compressed, very much branched and densely 

 caespitose, whitish or glaucous-brown, more or less sorediiferous ; 

 branches subsimple or dichotomously divided (Ca Cl-f- reddish, sore- 

 dia , medulla I -f bluish). Apothecia small, lecideine, black, naked 

 or slightly pruinose, somewhat prominent or appressed ; spores fusi- 

 formi-oblong, 0,012-16 mm. long, 0,003-4 mm. thick. Nyl. Syn. 

 i. p. 259, t. 8. f. 3 ; Gray, Nat. Arr. i. p. 426 ; Cromb. Lich. Brit. 

 p. 22 ; Leight. Lich. Fl/p- 81, ed. 3, p. 74. Rocetlla tinctoria ft. 

 phycopsis Mudd, Man. p. 75. Lichen fucoides Dicks. Crypt, fasc. ii. 

 p. 22. Lichen RocceUa With. Arr. ed. 3, iv. p. 42. Roccefla tinc- 

 toria Sm. Eng. Fl. v. p. 221 ; Mudd, Man. p. 75; Leight. Lich. Fl. 



