80 CYCLOCARPINEE [LEPTOGIUM 
thalline margin crowded with short crisp laciniz ; spores ellipsoid 
or broadly fusiform, 3-5-septate and muriform, 30-40 » long, 
13-17 p thick. Cromb. Lich. Brit. p. 9; Leight. Lich. Fl. p. 30; ~ 
ed. 3, p. 33. Lichen Burgessii Lightf. Fl. Scot. ii. p. 827, t. 26 
(1777); Huds. Fl. Angl. ed. 2, p. 538; Engl. Bot. n. 300; 
With. Arr. ed. 3, iv. p. 57. Collema Burgessii Ach. Lich. Univ. 
p. 645 (1810) ; Hook. Fl. Scot. ii. p. 71 & in Sm. Engl. Fl. v. 
p. 211; Tayl.in Mackay Fl. Hib. ii. p. 110. Mallotiwm Burgessit 
S. F. Gray Nat. Arr. i. p. 399 (1821); Mudd Man. p. 45. 
Exsice. Cromb. n. 6; Dicks. Hort. Sicc. fase. iii, n. 24. 
Well distinguished from all other Collemacex by the laciniate 
margin of the apothecium. The plant may be rather small and 
orbicular, or it may spread irregularly to a large extent. 
Hab. On the trunks of old trees near water (lakes and rivers), 
rarely on old walls, in wooded districts.—Distr. General and usually 
common in the western districts of the British Isles.—B. M. Ivy 
Bridge and Lydford, Devon; Nannau, near Dolgelly, Cwm-Bychan 
and Barmouth, Merioneth; Hafod, Cardiganshire; Mardale, West- 
moreland ; New Galloway, Kirkeudbrightshire ; Moffat and Rae Hills, 
Dumfriesshire; Head of Loch Awe, Inverary and Appin, Argyll; 
Glen Lochay, Inverarnan and Glen Falloch, Perthshire; Lochaber, 
Invernessshire; Eagle’s Nest, Cromaglown, Dinish and Derrycuintry, 
Killarney, Kerry ; Connemara, Galway. 
Orper VII. PANNARIACEZ:. 
Thallus not gelatinous when moist, heteromerous, granular, 
squamulose or foliose, with hypothallus and rhizine. Algal cells 
blue-green (Myxophycex), rarely bright-green (Chlorophycez). 
Apothecia disciform, with or without a thalline margin ; para- 
physes simple, or rarely branched ; spores 8 in the ascus, simple 
or septate, colourless or slightly brownish. Spermogones with 
upright septate sterigmata and cylindrical pleurogenous spermatia. 
Though containing blue-green algx, the Pannariacew differ from 
the previous Orders in the non-gelatinous heteromerous character of 
the thallus. The following genera are represented in the British 
Isles : — 
Algal cells Nostoc. 
Apothecia without a thalline margin; spores 
usdadly simple:.. i: issvcssssssrgueessteveqvias eaeee 28. Parmeliella. 
Apothecia with a thalline margin; spores 
usually Bimple:........is00ssdvescniay tevouh eae eeeee 29, Pannaria. 
Algal cells Scytonema. 
Apothecia without a thalline margin; spores 
L-septete..........cceccvecsessrecsscesensenceseneneeess 30. Massalongia. 
Algal cells bright-green (Dactylococcus ?). 
Apothecia with a thalline margin; spores 
BINDS... si0s-sciadonercedsonuerdavese recess wennch ins ... 31, Psoroma. 
