V. Remarks on Lichen scaber and some of ıts Allies. By the Rev, 
| Hugh Davies, F.L.S. = 
Read Jan. 15, 1811. MC cer. 
Accuracy and certainty, in the science of Natural History, 
are attainable but by gradations, and those sometimes minute, 
and of apparently little importance: any error therefore ob- 
viated, or discovery made, however trifling either may seem, 
may prove a step toward obtaining those ends. Care 
I feel confident that the very respectable names, which I must 
quote in the following essay, men of science and candour, whose 
main objects, in their researches, are the ends above stated, will 
pardon the liberty, which I must necessarily take, in observing 
a few mistakes with regard to two or three subjects now under 
consideration. * | 
A late accidental recovery, in Mr. Brewer's own original ha- 
bitat, near Borth, &c. of his plant, which is described by Dille- 
nius in his Hist. Musc. at page 66, Sp. 8. “ Usnea lane nigre 
instar saxis adherens,” which is mentioned again at p. 113, and 
figured in tab. xiii. fig. 8, has been productive of the following 
observations, which, perhaps, may not be thought unworthy of 
the notice of the Linnean Society, as they may assist in ascer- 
taining decisively two or three plants in the said work of Dil- 
lenius, and in dispelling a mist which has lately obscured them. 
Not 
