62 ANGIOCARPOUS LICHENS. 



40. V. MARGACEA, Wahl. Sporidia in asci 8, linear, 

 rounded at each extremity, triseptate, dark-brown. 

 PlateXXVI.fig. 3. 



Thelotrema margaceum, Wahl. in Ach. Meth. Suppl. (1803). 

 Verrucaria MARGACEA, Wahl. Fl. Lapp. 466. (1812) ; M. Suec. 872. 



Fnes, L. Ref. 440, 



Pyrenula MARGACEA, Ack. L. Univ. 315, t. 5, f. 3. (Apoth.) (1810) ; 



Syn. 127. 

 Verrucaria submersa, Borr. E. Bot. Suppl. 2768. (1833.) 



Sussex ! Mr. Borrer, 



The peculiarly expanded circumference of the peri- 

 thecium, visible through the thin thallus, distinguishes 

 this species at first sight. In an old state the prominent 

 portion of the apothecium falls off, leaving the expanding 

 circumference remaining as a black ring. 



Mr. Borrer, who has verified the above synonyms, 

 writes {in lit. 1850) : *' V, mhmersa is, I am much in- 

 clined to believe, V. margacea, Wahl., and if so it ought 

 to bear this name. I have no means of judging whether 

 Fries is right in referring V. hydrela and V. Morotica, 

 Ach. to the same species. V, hydrela of Mougeot 

 and Nestler's Crypt. Vosges. 952 belongs to ours. 

 Young specimens of this, in their native streams, are 

 bright green, and quite diaphanous. I doubt whether 

 you have seen * adulta et rite explicata' specimens such 

 as Fries describes." 



Schserer's specimen, No. 523, of V. cUorotica, Ach. is 

 a difierent plant. 



41. V. NiGRESCENS, FcTs. Sporidia in asci 8, oblong, 



margined, pale. Plate XXVII. fig. 1. 



Yerrtjcaria antiqtjitatis, Fl'drke, in Magaz. f. d. Neuest Enddeck 



in d. Naturk. 1807, i. p. 17. 



Verrucaria nigrescens, Pers. ap. Ust. in Ann. de Bot. st. 14. 36. 



Hook. Br. M. ii. 155 (in part.) (1833.) 

 Verrucaria umbrina /3. nigrescens, Ach. L. Univ. 291. (1810.) 

 Pyrenula nigrescens, Ach. Syn. 126. (1814.) 



Sussex ! Mr, Borrer, 



