USXEA.j TTSXEEI. 207 



Muse. 60, t. 11. f. 4. Lichenoides quod Muxcits arboreus no'losiis 

 Dill, in Kay, Syn. p. 65, n. 4. Brit. Exs.: Cromb. n. 17; Dicks. 

 Hort. Sic. n. 24. 



Apparently a distinct species, easily recognized by the articulate thal- 

 lns and the long capillary fibrils of the lateral branches. The rest of the 

 thallus is sometimes nearly efibrillose, and the articulations, few or 

 many, are caused by the transverse rupture of the cortical layer. In this 

 country the apothecia have never been met with, the supposed fruit of 

 the older writers being merely the " cephalodia," which are sometimes 

 very frequent and occasionally conglomerate. 



Hab. On the trunks of aged trees in old shady woods and forests in 

 upland districts. Distr. Local and scarce at the present day in Great 

 Britain, though before our old woods and forests were so extensively 

 felled it seems to have been much more frequent. B. M. : Charlton 

 Forest, Sussex; near Appuldurcomb and Ventnor, Isle of Wight; New 

 Forest, Hants ; near Exeter, Arton, Beckey Falls, Devonshire ; Liskeard, 

 Cornwall : Enfield Chace, Hertfordshire; near Stockenchurch, Oxford; 

 Cwra Bychan, near Barmouth, Merionethshire ; Burnley, Lancashire. 

 Stronaclachan Woods, Killin, Perthshire ; Deerhill AYoods, Forfarshire ; 

 liothieuiurchus AVoods, Inverness-shire. 



Form intestiniformis Cromb. Grevillea, xv. (1886) p. 48. 

 Thallus prostrate, thick, and inflated, here and there coarctate and 

 ventricose ; branchlets short, attenuate, flexuoso-interwoven. 

 Usnea barbata d. intestiniformis Ach. Lich. Univ. (1810) p. 625. 

 Usnea barbata ft. articulata Sm. Eng. Fl. v. p. 231. Usnea arti- 

 culata Tayl. in Mack. Fl. Hib. ii. p. 86. 



This singular state, evidently depending on the habitat, differs in the 

 articulations being very much swollen and the branchleta much shorter. 

 It is always infertile. 



Hab. On the ground in sandy tracts in maritime districts. Distr. 

 Local and scarce in S.W. England and S.E. Ireland ; not recently 

 gathered. B. M. : Exinouth Warren, Devonshire. Malahide, near 

 Dublin. 



Tribe XI. ALECTORIEI Nyl. Flora 1869, p. 444. 



Thallus fruticulose, rounded or compressed, erect or pendulous, 

 decumbent or prostrate, internally with lax, arachnoid me"dulla, or 

 entirely hollow. Apothecia lecanorine, scutelliform, lateral or 

 pseudo-terminal ; spores usually 8nae, small or moderate, simple, 

 colourless ; paraphyses not discrete. Spermogones immersed or 

 superficial ; sterigmata pauci-articulate. 



As instituted by Nylander this is a well-defined and natural tribe. It 

 is allied to the preceding and following tribes. Of its three genera, Du- 

 fourca and Dactylina do not occur in our Islands. 



