/■S'! [ 2218 ]
L ICHEN ulmi.
Elm Lichen.
CRYPTOGAMIA Algce.
G e n . C h a r . Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Crust leprous, white, thin, uneven, continued.
Shields numerous, sessile, concave, brownish
salmon-coloured, with a thick, white, powdery,
crenate, indexed border.
Syn. Lichen ulmi. Swartz. Nov. Act. Vpsal. v. 4. 247.
Ach. Prod. 54.
L. pallidus. Hoffm. Enum. 50. t. 5 , f . 2 .
Patellaria rubra. Hoffm. PI. Lich. v. 1 , 81. t. 1*1. ƒ. 2.
Parmelia rubra. Ach. Meth. 1 7 0 .
G a t h e r e d by Mr. W . Borrer on the hark of old elms
near Greta bridge, Yorkshire.
This is an elegant species. The very white leprous crust is
continued widely over the bark, but though occasionally rugged
or granulated, is commonly very thin. Numerous, and sometimes
crowded, shields are scattered over it, which are sessile,
with a very neat, thick, indexed, crenate, somewhat powdery
border, of the substance of the crust, and a concave disk of a
brownish salmon-colour, turning a little darker by age. When
old the disk- falls out, leaving the white border hollow like a
cup.
In our description of L. marmoreus, t. 739, we, like many
others, confounded this species with that. Having discovered
our error, we communicated it to Dr. Acharius, till then lying
under the same mistake, who has, with his usual candour,
corrected it in his Methodus, p. 170. Mr. Turner, on the authority
of a named specimen, suggests that our present plant
is Mr. Dickson’s marmoreus, but we are certain he comprehended
the real one also, which is cupularis of Hedwig, Crypt,
v. 2. 58. t. 20, B, and consequently of Acharius ; Mr. Dickson’s
cupularis being, according to Mr. Turner, L. Acharii,
figured in our t. 1Q87.
The white crust, place of growth, duller hue of the shields
and their pure white border, distinguish L. ulmi from marmoreus,
whose crust, when it can be detected, is of a dirty
green or grey, running over mosses and stones, its shields
redder, with a flesh-coloured wax-like border.
22JS.
A m i W o / iM e / A / ‘A v tr /yA ’/ / .