THE GREEN ALGAE OF NORTH AMERICA 315 



The pulvinate thallus distinguishes this species from all 

 others except C. pu/vinata ; the absence of a common center 

 for the filaments from the latter. 



Family 9. TRENTEPOHLIACEAE. 



Filaments branched, free or united into a membrane, cells 

 uni- or multinucleate, chromatophore generally band-shape, 

 sometimes breaking up into small disks, without pyrenoid ;* 

 chlorophyll masked by haematochrome, coloring the cells 

 yellowish-, brick-, or brown-red ; asexual reproduction by bicili- 

 ate zoospores, formed in sporangia borne on geniculate or 

 hooked cells ; the sporangia usually thrown off whole, the 

 zoospores emitted only when the sporangia are moistened ; 

 sexual reproduction by biciliate gametes, formed in sporangia 

 terminal on or intercalary in the vegetative filaments ; these 

 gametes often germinating without copulation. 



Aerial algae, with special adaptations to this mode of life. 



KEY TO THE GENERA OF TRENTEPOHUACEAE. 

 i. Basal layer a well developed disk ; erect filaments unbranched. 



3. CEPHALEUROS. 

 i. Filaments of basal layer not forming a disk ; erect filaments usually 



branched. 2. 



2. Filaments often bearing inarticulate setae. 2. NY^ANDERA. 



2. Filaments not setiferous. i. TRENTEPOHLIA. 



i. TRENTEPOHLIA Martius, 1817, p. 351. 



Basal filaments decumbent, producing erect filaments, simple 

 or branched, parallel or irregular, cylindrical to moniliform, 

 colored yellowish to red with haematochrome in the living 

 plant, fading when dried ; often with an agreeable violet odor ; 

 cells cylindrical to spherical, with band-shaped or broken chro- 

 matophore and no pyrenoid ; asexual reproduction by biciliate 

 zoospores, in sporangia borne on special hooked or curved cells ; 

 sexual reproduction by biciliate gametes in gametangia trans- 

 formed from vegetative cells, lateral, terminal, or intercalary, 

 spherical or ellipsoid. 



A genus of terrestrial algae, forming matted layers on rocks, 

 and on leaves and bark of trees. They range from arctic or high 

 mountain regions to the tropics ; most of the species are very 

 variable, and many species have been described based on charac- 

 ters of little permanence ; our species are here arranged after 

 Hariot, 1889-90, quite a number of species before generally rec- 

 ognized being given as synonyms or varieties. A curious adap- 



