34 



tuting an axis, which finally breaks up, or crowded into a more 

 regular layer between the cortical and at length parenchymatous me- 

 dullary layer. Apoth. globose or variously irregular. 



Genus 24. Ephebe. Apoth. globose. Spores simple, colorless. 

 Th. filiform, much branched, blackish-green, the gonimia not con- 

 catenate, finally somewhat stratified. A small genus of the Atlantic 

 coast. 3 spp., only one of which occurs with fruit. 



Genus 26. Lichina. Apoth. terminal, globose. Spores simple, 

 colorless. Th. fruticulose, brownish-black ; gonimia concatenate, 

 distinctly stratified. A small genus of maritime rocks. A form of 

 one sp. occurs in N. E., the peculiarities of which were first pointed 

 out by the writer to Prof. Tuckerman in 1868. It was described 

 and figured as " Thamnidium Willeyi Tuck.," by Schwendener in 

 1869, but without any material addition to the facts previously noted. 



Subfam. 2. Eucoliemei. Thallus foliaceous or squamulose, or 

 crustaceous ; rarely fruticulose ; the gonimia either concatenate and 

 dispersed in a gelatinous pulp among branching medullary filaments, 

 or clustered. Apoth. normally scutelteform, but sometimes in the 

 lower groups persistently globose. 



Genus 26. Pyrenopsis. Apoth. depressed-globose, urceolate, 

 or now at length open. Spores simple or 2 loc, decolorate. Th. 

 granulose. Gonimia concatenate or clustered, (and accompanied in 

 some spp. by gonidia.) A numerous genus of rock Lichens, 

 (rarely of earth,) of which 7 spp. are described with us, and more 

 doubtless occur. It includes here spp. of Synalissa, Nyl. Syn., and 

 Psorotichia, Mass., and Porocyphus Kbr. 



Genus 27. Omphalakia. Apoth. small, subglobose, more or 

 less immersed, or finally superficial and explicate. Spores simple, 

 colorless. Thallus fruticulose, or more commonly foliaceous, at- 

 tached by a single point. Gonimia clustered, or rarely concatenate. 

 A genus of numerous' spp., of which we have 9, one of wliich is 

 undescribed. It includes here Synalissa and Phylliscum, Nyl. Syn. 



Genus 28. Collema. Apoth. scutellseform. Spores either 

 simple or becoming fusiform and 2-plurilocular ; or commonly mu- 

 riform, scarcely coloried. Th. foliaceous, rarely fruticulose, mostly 

 dark-green, the cortical layer mostly indistinct. Gonimia almost 

 always concatenate ; medullary filaments conspicuous. A large 

 genus. 18 spp. and 9 subspp. 



Genus 29. Leptogium. Apoth. scutellffiform, zeorine or biato- 



