COLLEMA.] COLLEMEI. 57 



the gonimia being not moniliform but glomeruloso-congested. The apo- 

 thecia are usually scattered over the whole thallus almost to the apices of 

 the lacinise. 



Halt. On shady calcareous rocks and walls in maritime and upland 

 districts. Distr, Sparingly here and there in Great Britain, S. and W. 

 Ireland. B. M. : Mendip Hills and near Yatton, Somersetshire ; Dovedale 

 and Buxton, Derbyshire ; Oswestry, Shropshire ; Nant Glyn, Denbigh- 

 shire ; Settle, Yorkshire; Teesdale, Durham; Haversham Head and 

 Cimswick Scar, Westmoreland; Lanaplugh, Cumberland. Achosragan 

 Hill, Appin, and island of Lismore, Argyleshire ; shores of Loch Tay and 

 Ben Lawers, Perthshire. Middletou, near Cork ; Kenmare and O'Dono- 

 ghue's Prison, Killarney, co. Kerry ; Kylemore, co. Galway. 



25. C. isidioides Nyl. ex Arn. -Flora, 1870, p. 232. Thallus 

 granuloso-aggregate (isidioid), blackish, in subpulvinate glomeruli. 

 Apothccia and spermogones unknown. Nyl. Flora, 1883, p. 98; 

 Cromb. Journ. Bot. 1885, p. 195. 



The place of this species in the genus is uncertain in the absence of 

 fructification. Detected by Arnold in the Bavarian Alps, Nylander 

 observes that the " thallus consists of a congeries of syngonimia (sub- 

 globose or oblongo-dift'orm), with the filaments often indistinct." 



Hal). On calcareous rocks in mountainous districts. Distr. Gathered 

 only in N.W. England (Warton Craig, Westmoreland). 



15. COLLEMODIUM Xyl. ex Lamy, Bull. Soc. Bot. Fr. 

 t. xxv. (1878) p. 341 ; Nyl. Flora, 1875 (ut subgen us). Thallus 

 small or submoclerate, 

 variously lobed or 

 subfruticnlose ; corti- 

 cal layer somewhat 

 distinct; gonimia 

 more or less scattered, 

 partly moniliform. 

 Apothecia urccolate, $%>ll 9 



lecanorine, rarely bi- 



, . J 



atonne ; spores 8me, 



ovoid or ellipsoid, 



colourless, variously Collemodium fluviatile NyL-a. Vertical section 



septate and divided; of thallus, x275. b. Gonirnic granules sopn- 



hymenial gelatine rated from the cells. 



deep blue with iodine. Spermogones with jointed sterigmata and 



straight spernmtia obsoletely incrassate at either apex. 



Instituted by Nylander for various plants previously arranged chiefly 

 under Cottema. From Collcma it differs in the cortical layer being 

 distinct, though usually but slightly apparent. It thus forms a transition 

 between Collema and Homodium, a subgenus of Leptoyium to which it 

 is closely related. The fructification is similar to that of Leptogium. 



1. C. biatorinum Nyl. ex Cromb. Grevillea, xv. (1886) p. 12. 

 Thallus effuse, minutely granuloso-lobulate, imbricate, brown or 



