PIIYSCIA.] PUYSCIKr. '.i'2\ 



i. J). 4'.VJ. Squamaria elaliri Sm. Eiij;". Fl. v. p. 1!)7. Lichen 

 eUeinus Eng, But. t. 2ir)S. —liril. Kvs. : Cromb. ii. I ")2 ; ]/irb. Lich. 

 lib. n. 49. 



The tlialliis is often leproso-piilverulent in the centre, and sometimes 

 Rubeflfuse, tlirough tlie continence of several plants. From states of /■•. 

 obscura, of whicli it has frequently been considered as a variety, it at 

 once differs in the form of the spermatia. Tiie apothecia are chielly 

 central. The spernio^ones. which are not uncommon, are olive-bruwn, 

 with spermatia long', acicular, about 0,016 mm. long, s.-arcelv 0.001 mm. 

 tiiick. 



Hab. On the trunks of trees, rarely ou walls, in maritime and lowland 

 districts.— i'/!(C;-. Probably not uncommon throughout England and W. 

 Ireland ; rare in the Channel Islands ; apparently absent from Scotland. 

 — B. M. : Xoirmont, Island of Jersey. Norwich, Norfolk ; Waltharastow, 

 Es.sex ; Glynde, Ilurstpierpoint, and between Ilenfield and Brighton, 

 Sussex; Lymington, Ilants; Penzance, Cornwall; near Cirencester, 

 Gloucestershire; Gamhngav, Cambridgeshire; Cleveland, Yorkshire; 

 Kendal, Westmoreland. Killarney, co. Kerry ; Kylemore, co. Galway. 



Form sorediata Nyl. ex Leight. Lich. Fl. ed. 3 (1879) p. 138.— 

 Thallus leproso-sorediate almo.st throughout, glaucous- white ; lacinise 

 more dilated at the circumfereace and there only esorediate. Apo- 

 thecia uot seen. — Brif.. Exs. : Larb. Lich. Hb. a. 127. 



Apart from the paler colour and the broader lacinine this ditfois only 

 in the much more sorediate thallus, in which respect it resembles var. 

 suboirella Xyl. (Pyr. Oi'. p. G;5), which does uot occur in our Islands. 

 The specimens seen are sterile. 



llab. On walls and trees in upland districts. — Distr. Oulv sparingly in 

 N.W. Ireland. — B, M. : Letterfrack and Letter llill, Conuemara, co. 

 Galwav. 



Tribe XYIL GYROPHOREI Xyl. Mem. Soc. Cherb. 

 iii. (1855) p. 175; Lich. Scaud. p. 112. 



Thallus membranaceo-foliaceous, monophyllous or subpolyphyllous, 

 peltate, umbilicately affixed iu the centre to the substratum, cor- 

 ticate on both surfaces ; internally with white lax filamentose 

 medulla ; gonidial layer containing gonidia. Apothecia either leca- 

 noroid, or lecideiue and gyrose, black ; spores solitary or usually 

 Suae, oblong or ellipsoid, simple or murali-divided, colourless or 

 brown ; paraphyses discrete. Spermogones either immersed or 

 somewhat prominent, with jointed sterigmata. 



The systematic position of this tribe has been variously regarded by 

 authors. There is no doubt, however, that this is its true place as indi- 

 cated by the character of the vegetative and reproductive organs, though 

 the structure and form of the apothecia are rather peculiar. It is a very 

 natural tribe, comprising two genera, the distinctive characters of which 

 have recently been definitely pointed out by Nylander. The species are 

 all saxicolous, characteristic of cold regions, and for the most part very 

 brittle when drv. 



T 



