306 LICHENACEI. [PHYSCIA. 



numerous, and the spermogones, -which are not uncommon, have the 

 spermatia equally cylindrical, 0,006 mm. long, about 0,001 mm. thick. 



Hab. On the trunks and branches of trees, and on old pales, rarely 

 erratic on stone walls, chiefly in cultivated lowland and upland districts. 

 Distr. General and common throughout Great Britain and probably 

 Ireland, becoming rare in N. Scotland ; rare in the Channel Islands. 

 B. M. : Island of Guernsey. Bury St. Edmunds, SuiFolk ; Epping Forest, 

 Essex ; Edgeware, Middlesex ; Hurstpierpoint and Lewes, Sussex ; near 

 Hyde, Isle of Wight ; Wembury, Devonshire ; near Withiel, Cornwall ; 

 Bourn, Cambridgeshire ; Milton, Oxfordshire ; Bolton Abbey, Lincoln- 

 shire ; Twycross, Leicestershire ; Moor Park, Herefordshire ; Crowle, 

 Worcestershire ; near Shrewsbury, Shropshire ; Aberdovey and Anglesea, 

 N. Wales ; Ayton, Cleveland, Yorkshire ; Middleton, Teesdale, Durham ; 

 Kendal, Westmoreland. Largs, Ayrshire; near Edinburgh; Appin, 

 Argyleshire; Killin and Blair Athole, Perthshire; Cults, near Aberdeen, 

 and Abergeldie Castle, Aberdeenshire ; Applecross House, Ross-shire ; 

 Carrigaloe and Aghada, co. Cork ; Ballynegarde, co. Limerick ; Dun- 

 kerron, co. Kerry. 



Form 1. panniformis Cromb. Journ. Linn. Soc. Bot. xvii. (1880) 

 p. 571; Jourri. Bot. 1882, p. 273. Thallus with the lacinife short, 

 crowded, densely imbricate. Apothecia small. Lichenoides ylaucum 

 orbiculare, segmentis latiusculis, scutellis niyris Dill. Muse. 177, t. 24. 

 f. 71 D. 



One of those panniform conditions of foliaceous lichens which have 

 recently been noted, forming as it were a thickish congested crust, the 

 lacinise presenting their normal appearance only at the extreme circum- 

 ference of the thallus in entire specimens. In the fertile plants seen, the 

 apothecia are few and small, with the receptacular margin thickish. 



Hab. On the trunks of old trees in upland districts. Distr. Only in 

 W. England and among the Central Grampians, Scotland. B. M. : Ilar- 

 boro' Magna, Warwickshire. Craig Tulloch, Blair Athole, Perthshire. 



Form 2. deminuta Cromb. Journ. Bot. 1882, p. 273. Thallus 

 effuse, more or lees diffract, the latinise minute. Apothecia very 

 small, pruinose. 



Probably only a starved condition of the preceding form, in which the 

 laciniae are either somewhat congested or scattered. In our few speci- 

 mens the apothecia are, with one exception, very sparingly present. 



Hab. On the trunks and branches of trees in maritime and upland dis- 

 tricts. Distr. Only sparingly in S. and W. England, S. Wales, and the 

 Channel Islands. B. M. : Island of Guernsey. Shanklin and Appuldiu- 

 combe, Isle of Wight ; near Cirencester, Gloucestershire ; Ltolgelly, 

 Merionethshire. 



Form 3. argyphea Nyl. Lich. Scand. (1861) p. 104. Thallus 

 entirely white-pruinose ; lacinise somewhat firm and slightly dilated 

 at the circumference. Apothecia constantly pruinose, the receptacle 

 often unequal or sometimes subcrenulate. Cromb. Journ. Linn. Sr c. 

 Bot. xvii, p. 571. Parmelia pulverulent a ft. argyphea Ach. Lich. 



