CATALOGUE OF PLANTS. 247 



C. pulvinata (Mert.), Ag. 



On piles of bridge, outlet of Long Pond (Collins). Rare; the 

 most northern station for this species yet reported. 



RIVULARIA, Roth. 

 R. atra, Roth. 



Common in upper tide pools (Collins) ; Sea Wall (Holden). 

 R. nitida, Ag. R. plicata, Farlow's Manual, 38. 



On woodwork; rare (Collins). 



MASTTGOCOLEUS, Lagerh. 



Trichome of a single series of cells, blue-green or yellowish, 

 .006-. 01 mm. diam., branching, the branches sometimes of uni- 

 form diameter, sometimes tapering to a fine hair. Heterocysts 

 terminal or lateral ; spores unknown. Appears as a blue-green 

 stain on the surface of the shell. 



M. testarum, Lagerh. 



Growing in the substance of dead shells, in company with 

 Hyella ccespitosa, etc. Seal Harbor (Collins). The only species 

 of the genus. 



STIGONEMA, Ag. 

 S. mamillosum, Ag. 



On rocks in outlet of Hadlock Lower Pond (Holden). 



MICROCOLEUS, Desmaz. 



M. chthonoplastes (El. Dan.), Thuret. 



Very common in lagoon, Little Cranberry Isle (Collins) j 

 shore west of Bracy Cove (Holden). 



LYNGBYA, Ag. 

 L. asstuarii (Juerg.), Liebm. 



Very common in lagoon, Little Cranberry Isle ; occasional 

 near Seal Harbor (Collins). 



