226 LICHENES. 



[Usnea. 



greenish inflexed smooth border. Sm. — Ach. Syn. p. 298. — 

 Lichen pollinarius, Ach. Prodr. — E. Bot. t. 1607. — Dijl Muse. 

 t.2l.f. 57. 



On old trees, posts and rails, rarely on rocks, in England. Particu- 

 larly abundant in Norfolk and Suffolk, on old barn-doors, which are some- 

 times covered with the plant. 



b. Thattus subcylindrical, filamentous^ nearly pendent. 



a. Thallus with a central thread. Apothecia scutelliform, without 

 a border ; ciliated (orbillai). 



FAM. XIV. UsNEiE. 



31. Usnea. Ach. Usnea. 



Thallus subcrustaceous, rounded, branched, generally pendu- 

 lous, with a central thread. Apothecia (orbiflce,) orbicular, ter- 

 minal, peltate, entirely formed of the substance of the thallus 

 and nearly of the same colour, the circumference mostly with- 

 out a border and (generally) ciliated. — Name ; from dchneh or 

 dchnen, in Arabic (Axneeh or Usnee, according to Dillenius,) 

 the name of some Tree-Lichen. 



1. U. fiorida, Ach. (fioivery Usnea); thallus nearly erect 

 rough greenish-grey branched, the main branches bearing in- 

 numerable small horizontal nearly simple fibrous ones, apothe- 

 cia plane large pale flesh-coloured bordered with long radiating 

 fibres or cilia. — Ach. Syn. p. 304. — Lichen Jloridus, Linn. — 

 E. Bot. t. 872.— Dill. Muse. t. 13. /. 13. 



Branches of old trees, frequent in hilly and mountainous countries. 



2. U. pliedta, Ach. (stringy Usnea); thallus pendulous smooth 

 pale, branches lax much divided subfibrillose the ultimate ones 

 capillaceous, apothecia plane broad ciliated, the cilia slender 

 and very long. Ach. Syn. p. 305. — Lichen plicatus, Linn. — 



E. Bot. t. 257.— Dill. Muse. t. 11. /. 1 (3. hirta; nearly erect 



greyish-green much branched scabrous bearing flesh-coloured 

 solid warts, branches very much divided flexuose intricate sub- 

 fibrillose — Ach. Syn. p. 305. — Lichen hirtus, Linn. — E. Bot. 

 t. 1354.— L. Jloridus, /§. Buds.— Dill. Muse. t. 13./. 12. 



Common on old trees and park-pales, both «. and /•. — The Lichen 

 hirtus of Linnaeus and E. Bot., Acharius has referred to the Usnea pli- 

 cata; but to me it appears to have a nearer affinity with U.florida, and 

 the distinctions between that and the present species are very unsatis- 

 factory and I fear not much to be depended upon. Indeed the Lichen 

 plicatus of E. Bot. looks more like the U. barbata ; and Sir J. E. 

 Smith observes that the main-stems often crack here and there, as is the 

 case with that species : and then I do not see how they are to be distin- 

 guished. 



3. U. barbata, Ach. (jointed Usnea); thallus pendulous 



