534 



BULLETIN OF THE BUREAU OF FISHERIES. 



cc. Filaments branched t. 



. Filaments lacking heterocysts HYDROCOLEUM (p. 413). 



ii. Filaments possessing heterocysts PLECTONEMA (p. 415). 



A A. Color green; filamentous or forming tubes or sheets or complex structures of various 

 shapes composed of closely interwoven filaments; usually attached, sometimes float- 

 ing; some forms minute, living on or in shells or other algae; some forms incrusted 



with lime II. CHLOROPHYCE^E- 



a. Frond fiat, expanded 6. 



b. Outline irregular, indefinite, usually floating, attached when young ULVA (p. 420). 



bb. Outline regular, definite; usually attached Enteromorpha linza (p. 420). 



aa. Frond forming a hollow tube c. 



c. Wall of tube composed of cells ENTEROMORPHA (p. 418). 



cc. Wall of tube not cellular, tube consisting of single unsegmented cavity of various 



complicated forms .d. 



d. Frond consisting of an upright stalk arising directly from the base, pinnately 



branched above BRYOPSIS (p. 431). 



dd. Frond consisting of a creeping stem attached at intervals, from which arise erect 



branches of various forms CAUI,ERPA (p. 434). 



aaa. Frond filamentous . 



e. Frond microscopic, invisible to naked eye or visible only as a green stain on the sub- 

 stratum ./. 



/. Frond living in walls of other algae ENDODERMA (p. 423). 



ff. Frond living on surface of shells ULVELLA (p. 423). 



fff. Frond living within surface of shells GOMONTIA (p. 429). 



ee. Frond easily visible to naked eye ^ g. 



g. Filaments unsegmented, loosely interwoven to form an irregular mat DERBESIA (p. 430). 



gg. Filaments segmented at regular intervals h. 



h. Filaments unbranched CH^ETOMORPHA (p. 424). 



hh. Filaments regularly branched ; attached or floating CLADOPHOR A (p . 42 7 ) . 



hhh. Filaments usually with few irregular, rhizoidlike branches, sometimes un- 

 branched, usually not attached RHIZOCLONIUM (p. 427). 



aaaa. Frond composed of branched filaments closely interwoven to form a complex structure, i. 



'. Frond fan shaped on an evident stalk, incrusted with lime UDOTEA (p. 433 ). 



ii. Frond terete or somewhat flattened, dichotomously branched, spongy, not incrusted 



with lime CODIUM (p. 432). 



AAA . Color brown, sometimes with greenish tinge ; filamentous or forming complex structures 

 of various shapes; usually attached; some forms minute, living on or in other algae 



III. PH^SOPHYCE^. 



a. Frond filamentous. 6. 



b. Frond easily visible to naked eye ECTOCARPUS (p. 437). 



bb. Frond microscopic, almost or quite invisible to naked eye c. 



c. Frond growing on the surface of other algae d. 



d. Frond more or less spherical in outline, composed of decumbent radiating 



filaments united to form a basal layer from which arise erect filaments . MYRIONEMA (p. 445). 

 dd. Frond having no regular outline, composed of decumbent, irregularly dichto- 



mous filaments PH,BOSTROMA (p. 442). 



cc. Frond growing within the surface of other algae e. 



e. Frond forming its fruits above the surface in more or less spherical, dense 



clusters ELACHISTEA (p. 444). 



et. Frond forming its fruits above the surface singly or in irregular, loose groups 



STREBLONEMA (p. 440). 



aa. Frond, small globose, hollow LEATHESIA (p. 447). 



aaa. Frond mostly terete, with distinct central axis and lateral branches ./. 



/. Frond with many lateral branches leaflike, giving the appearance of stem and 



leaves, usually with berrylike floats SARGASSUM (p. 451). 



