USNEA. ] USNEEI. 207 
Muse. 60, t. 11. f. 4. Lichenotdes quod Museus arboreus norlesus 
Dill. in Ray, Syn. p. 65, n. 4. Brit, Hvs.: Cromb. n. 17; Dicks. 
Hort. Sic. n. 24. 
Apparently a distinct species, easily recognized by the articulate thal- 
lus and the long capillary tibrils 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 occa-ionally 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, 
Corawall; Enfield Chace, Hertfordshire; near Stockenchurch, Oxford ; 
Cwm Bychan, near Barmouth, Merionethshire; Burnley, Lancashire. 
Stronaclachan Woods, Killin, Perthshire; Deerhill Woods, Forfarshire ; 
Rothiemurchus Wocds, 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. 628. 
Usnea barbata B. articulata Sm. Eng. Fl. v. p. 231, Usnea arti- 
culata Tay]. 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 branchlets 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 8.E. Ireland; not recently 
gathered.—B. M.: Exmouth 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 medulla, or 
entirely hollow. Apothecia lecanorine, scutelliform, lateral or 
pseudo-terminal; spores usually 8ne, 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- 
fourea and Dactylina do not occur in our Islands, 
