L IC H E N diatrypus.
Perforated Lichen.
CR YPT0GAM1A Algce.
Gen. Ch a r . Male, scattered warts. Female, smooth
shields or tubercles, in which the seeds are imbedded.
Spec. Ch a r . Imbricated, depressed, composed of a
double membrane, black beneath, pale grey above ;
segments obtuse, inflated and perforated. Shields
concave, small, reddish.
Syn. Lichen diatrypus. Achar. Prod. 116.
L. pertusus. Schrad. Spirit. 96.
Parmelia diatrypa. Achar. Meth. 251.
Lobaria terebrata. Hojpm. Germ. v. 2. 151.
O n mossy rocks and trees in alpine situations, but never
observed in Britain, till Mr. Turner gathered it at Beddgelart
at the foot of Snowdon in the summer of 1800.
Wulfen, who has given a figure of this Lichen without
fructification in the 3d vol. of Jacquin’s Collectanea, confounds
it with L . physodes, see our v. 2. t. 126. Dr. Schrader
first pointed out their true differences. They both indeed
consist of a double membrane, with a considerable vacuity
between the two coats, as is the case with 2 or 3 American
species lately discovered by the accurate Mr. Menzies; but
L . diatrypus, besides being more depressed, with a certain
air of neatness and regularity in its lobes, is remarkable for
having a regular round perforation in the middle of most of
its segments, quite through the upper coat. The shields are
also, as Schrader well remarks, but half the size of those of
physodes, nearly sessile, smooth, not wrinkled, in their margin
and outside. Powdery warts in abundance grow on the
same plant with the shields.