LECANOBA.] 



LECANO-LECIDEEI. 



357 



i. 4. PLACODIUM Nyl. Not. Sallsk. pro F. et Fl. F. 

 Forh. v. (1866) p. 126. Thallus radiating, usually effigurate at the 

 circumference. Apothecia often at length subbiatorine ; spores 8nse, 

 ellipsoid, polari-bilocular, usually with longitudinal tube, very 

 rarely simple or subsimple ; hymenial gelatine (especially the 

 thecae) bluish with iodine. Spermogones with shortly jointed 

 sterigmata, and straight, oblong or bacillifortn spermatia. Placo- 

 dhnn DC. Fl. Fr. ii. (1805) p. 377; Nyl. Mem. Soc. Cherb. iii. 

 p. 177. 



Fig. 61. 



Lecanora (Placodium) callopisma Ach. a. Vertical section of thallus, X 200. 

 b. Three spores, X 500. c. Sterigmata and spertnatia, X 500. 



Known by the more or less radiose thallus (which is variously yellow, 

 very rarely whitish), by the usual mode of division of the spores, and by 

 the short arthro'steriginata. The spermogones are externally somewhat 

 prominent, with the ostioles in the yellow thalli orange-yellow. 



9. L. fulgens Ach. Lich. Univ. (1810) p. 437 ; Nyl. ex Hue, 

 Revue Bot. 1886, p. 21. Thailus orbicular, submonophyllous, 

 adnate, opaque, laciniato-divided at the circumference, pale yellow 

 or citrine; laciniae crenate or crenato-lobulate(K-f- reddish-purplish). 

 Apothecia small, plane or convex, orange-coloured, K + purplish, the 

 thalliue margin concolorous, at length obliterated ; spores simple, 

 0,009-12 mm. long, 0,005-6 mm. thick. Placodwm fulgens Gray, 

 Nat. Arr. i. p. 447 ; Mudd, Man. p. 131 ; Cromb. Licli. Brit. p. 45 ; 

 Leight. Lich. Fl. p. 178, ed. 3, p. 164. Squamaria fulgens Sm. Eng. 

 Fl. v. p. 195. Lichen fulgens Sw. N. Act. Upsal. iv. (1794) p. 246 ; 

 Eng. Bot. t. 1667 ; Dicks. Crypt, fasc. iv. p. 24. Brit. Exs. : Larb. 

 Caesar, n. 27 ; Lich. Hb. n. 296 ; Cromb. n. 155. 



From the simple spores this might be referred, as ha*$ often been done, 

 to submenus SyuaiHaria. Its true place, however, is shown by the 



