VOL. L.] PHILOSOPHICAL TRANSACTIONS. '251 



ture, having the appearance of fructification in the form of scutellas, or flat round 

 bodies growing from the sides or extremities of these filaments. 



This order or division comprehends the hairy tree-mosses, or usnea of Dil- 

 lenius and Hill ; several of the species of the 5th order of lichens of Micheli ; and 

 the lichenes filamentosi of Linneus. 



Dr. Dillenius describes id species under the term usnea, several of which are 

 found in England, though some of them, as the common usnea of the shops, 

 but very sparingly, and none of them in any considerable plenty. The thick 

 woods in many other parts of Europe, and the rest of the globe, afford them in 

 great plenty. They hang from the branches of various kinds of trees, like large 

 tufts of hair, to a considerable length : some species grow several feet long. The 

 rocks on the tops of high mountains afford several kinds. They are of various 

 colours ; some whitish, ash-coloured, others grey or blackish, and 2 or 3 species 

 have a yellow or orange hue. 



The commentators in general agreed in making the bryon* of Dioscorides one 

 of these hairy tree-mosses, which they called usnea. No wonder therefore that 

 at the restoration of letters it became a matter of controversy, which of them 

 was the usnea of the ancients. Dioscorides recommends his as an astringent ; 

 and tells us, that ' the best grew upon the cedar ; but that from whatever tree 

 it was gathered, the whitest and most fragrant was preferable to the black.' The 

 several usneae would doubtless in different countries be found upon different 

 trees. In Italy, that of the larch-tree was the most odoriferous ; and on that 

 account Matthiolus preferred -i^ it to all others. That kind, which at length ob- 

 tained a place in the shops as the usnea of the ancients, was a species commonlj'^ 

 found in our countries on old oaks and other trees, and is called by Dillenius t 

 stringy tree-moss, or usnea of the shops. Many excellent virtues have been as- 

 cribed to it, on a supposition of its being the true usnea ; but it does not appear 

 to have deserved them : and the present practice, at least in England, has quite 

 expunged it, and that perhaps very justly. Dr. Dillenius is evidently of opinion 

 however, that this common usnea, though it obtained a place in the shops as 

 such, is not the bryon of Dioscorides and Pliny, or the phaseon of Theophrastus, 

 since he has applied these names from those fathers of botany to another species, 

 which he calls the beard ^ usnea. Nor does either of these species appear to be 



• Lib i. c. 20. See this subject largely discussed in Bodaeus a Stapel Comment, in Theoph. p. 

 156" et seq.— Orig. 



I Opera omnia a C B. ed. 139S. p. 64. — Orig. 



X Usnea vulgaris loris longis implexis Hist. Muse. p. 56, Lichen plicatus Lin, Sp. PI. 1154. 

 Muscus arboreus : usnea officin. C. B- Raii Syn. iii. p. 64^. — Orig. 



§ Usnea barbata loris tenuibus fibrosis Hist. Muse. p. 63. £-ichen barbatus Lin. Sp. PI. 1155. 

 Quercus excrementum villosum C. B. p. 422. Bauhia toftk .tiws^to ^,tb£i4?;V^i=>isQea Arabum, — 

 Orig. ■'' - 



K K 2 



