_ 284 Rev. Mr. Daviss's Defcriptions 
Since the drawing of it was taken, I have likewife found it 
on a fand-ftone, and then, owing to the unevennefs of the 
furface, the fructification affumes a {till more irregular form, fome- 
times appearing in fimple lines, and fometimes coiled; in fome de- 
gree refembling the fruétification of Lichenoides, t. 29. f. 116. 
Dill. Hif Muf. 
Found with the former. 
3. L. CONCENTRICUS*. 
L. cruftaceus albidus, fcutellis fubimmerfis confluentibus concen- 
tricis atris. 
Concentric Lichen. 
THE fcutelle are fcarcely raifed above the ground, depreffed 
in the centre, and have a margin which varies in colour, being 
fometimes white, fometimes black. I could have fuppofed this to 
be L. petræus, Jacq. Collect. T. 3. tab. 6. f. 2. litt. a. a. a. from his 
figure; but he refers to Michelius, ord. 34. p. 99. n. 53. and to 
Hall. Helv. nos. 2061 and 2062, whofe defcriptions by no means 
accord with this plant; particularly, as neither of thofe accurate 
~ authors has noticed the confluent fru&ifications, which invari- 
. ably form concentric fegments of a circle, affording a moft diftin- 
.. guifhing charaéteriftic. 
- . Found in Whitford parifh, Flintfhire. 
4 L. varians. Tas. 28. f. 3. 
L. cruftaceus albus, fcutellis atris nitidis : margine albo. 
Changeable Lichen. 
BY the feveral variations of this plant, — at the figures 
- A. B. C. D. it is evident that it varies exceedingly in refpeét of co- | 
* L. petreus, Jacq. Coll. v. 3. 116. t. 6. f. 2. lit. a. a. a. fynonymis dubiis. 
lour, 
