CATALOGUE 



OF 



BRITISH LICHENS. 



PAET II. 



Family III. LICHENACEI (continued). 



Tribe XVIII. LECANO-LECIDEEI (continued). 



Subtribe IV. THELOTBEMEI (continued). 



67. CONOTREMA Tuck. Syn. N. Amer. Lich. i. p. 217 

 (1882). (PI. 1.) 



Thallus crustaceous, membranaceous, uniform ; algal cells 

 (gonidia) Protococcus. Apothecia urceolate, immersed, truncate- 

 conoid at first closed then open, becoming plane, proper margin 

 black, thalline margin thin, soon disappearing ; spores long, 

 cylindrical, colourless, multiseptate. Spermogones with simple 

 sterigmata and oblong straight spermatia. 



This genus is retained in the Thelotremei on account of the 

 urceolate, double-walled apothecium. The spores are very dis- 

 tinctive. 



1. C. urceolata Tuck. I. c. — Thallus glaucous, white or greyish, 

 smooth, becoming wrinkled or cracked, membranaceous, limited 

 by a black line. Apothecia small, black, urceolate, becoming 

 sessile and prominent, whitish-pruinose or naked, with a thick, 

 elevated margin ; hypothecium blackish ; paraphyses slender, lax, 

 branched above, colourless ; spores 8nate, elongate-cylindrical, 

 maggot-like, somewhat arcuate, 30-40-septate, 0,100-160 mm. 

 long, 0,003-5 mm. thick. — Lecidea urceolata Ach. Lich. Univ. 

 p. 671 (1810) ; Cromb. in Journ. Bot. xiii. p. 141 (1875) ; Leight. 

 Lich. FI. ed. 3, p. 361. 



jQ^ Hab. On the bark of rather smooth trees. — Diatr. Eare, only 

 recorded from W. Scotland. — B. M. Airds, Appin, Argyll. 



