168 LEOANOKEL EULECANOREI. 



H. venosa, Russell ; thallus ample, loosely aggregated, thin 

 .and fragile, laciniate-lobate ; lead-coloured ; beset beneath with 

 branched, divaricate, pale-brown veins ; lobes more or less fan- 

 shaped, irregularly cut, with rounded, repand-crenate summits ; 

 apothecia sub-marginal, middling-sized ; the disk reddish-brown, 

 .soon convex, and excluding the pale, lacerate-dentate margin. 

 Spores cymbiform, and fusiform, 4-locular, decolorate, ^f mic. 



Buss, in Proc. Essex Inst. 1, p. 188. Tuckerm. Gen. p. 102. 



H. fontana (Russ. olim), Tuck. Lich. exs. n. 150 (sub Lept.). 

 Nyl. Syn. I, p. 135. 



On stones under water in mountain brooks, Vermont and New 

 Hampshire, Eussell I. c. 1856. Connecticut, Prof. D. C. Eaton. 

 Mariposa, California, Bolander. 



Fam. 7. LECANOREI. 



Thallus crustaceous j very rarely papillose-ramulose ; in 

 a much larger number of instances lobed at the circumfer- 

 ence, or squamulose and sub-imbricate; but, in far the 

 greater proportion, uniform ; adnate to the substrate; the 

 hypothallus inconspicuous or obsolete. Gen. p. 103. 



We revert, in the family now before us, from the extraordi- 

 narily differenced but still Parmeliaceous Collemei to the remote 

 Parmeliei. Of this, the first Sub-Family (Eulecanorei) may be 

 easily regarded as a contiguous section, differing as it scarcely 

 does otherwise than in its crustaceous instead of foliaceous thal- 

 lus. But this distinction in the thallus has been proved to have 

 value in the system; and the Eulecanorei pass, without a break, 

 into the very marked, crustaceous Sub-Family which is dis- 

 tinguished by its typically compound fruit (Pertusariei) as this 

 last stands in close relation to forms even more alien to the tribal 

 type (Sub. -Fam. Urceolariei), suggesting now (and often indeed 

 referred to) Lecideacei ; and Verrucariacei ; and even, we might 

 add, Graphidacei. 



Sub. -Fam. 1. EULECANOREI. 

 Apothecia scutellseform. 



