C A T A L O G U E
OF
B E I T I S H L I C H E N S
PART II.
Family I I I . L IC H E N A C E I (continued).
Ti’ibe X V I I I . L E C A N O - L E C ID E E I (continued).
Subtribe IV . TM E LO TB EM E I (continued).
67. CONOTREMA Tuck. Syn. N. Amer. Lich i p 217
(1882). (PI. 1.) ■
Thallus crustaceous, membranaceous, uniform ; algal cells
(gonidio) Protococcus. Apothecia urceolate, immersed, truncate-
conoid a t 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 distinctive.
1. C. urceolata Tuck. Z. 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); Cromh. in Jo u rn . Bot. xiii. p. 141 (1875); Leight.
Lich. PI. ed. 3, p. 361.
^ Hab. On the bark of rather smooth trees.—Distr. Rare, only
recorded from W. Scotland.—B. M. Airds, Appin, Argyll.
II. 33