4 Charles E. Bessey 



Phylum IV. SIPHONOPHYCEAE. The Tube Algae. 



Plants coenocytic, filamentous, or saccate, often much branched, 

 and usually basally attached by rhizoids, from septate (consisting 

 of rows of coenoc}-tes) to non-septate, the filaments single or 

 aggregated into a plant body of definite form; chromatophores 

 discoid or reticulated, parietal ; propagation by ( i ) the internal 

 division of the protoplasm of a part (sporangium), or of the 

 whole plant into spores, — in water into zoospores, — in the air 

 into walled spores; or by (2) the contraction of definite masses 

 of protoplasm into agamic resting-spores (aplanospores or 

 chlamydospores) ; generation by the union of (i) ciliated iso- 

 gametes, (2) ciliated heterogametes, or (3) sperms with non- 

 ciliated gynogametes (eggs), or of (4) antherid nuclei (non- 

 ciliated) with eggs, in all cases producing zygotes. Typically 

 freshwater and marine algae (holophytes), from which many 

 filamentous fungi (hysterophytes) have been derived. 



Class 7. VAUCHERIOIDEAE. Lower Tube Algae. Plants 

 filamentous, septate or tubular. (About 800 species.) 



Order Cladophorales. The Cladophoras. Filaments septate, 

 the segments coenocytic. 



Family i. Cladophoraceae. Filaments simple or branched, 

 basally attached; isogamic. Rhizoclonium, Cladophora, Pitho- 

 phora. (Pf. I, 2, 114.) 



Family 2. Sphaeropleaceae. Filaments simple, unattached, het- 

 erogamic. Sphaeroplea. (Pf. I, 2, 121.) 



Order Siphonales. iGreen Felts. Filaments tubular, irregu- 

 larly branched ; chlorophyllose holophytes. 



Family 3. Phyllosiphonaceae. Endophytic and parasitic in the 

 tisssues of higher plants. PhyUosiphon. (Pf. I, 2, 125.) 



Family 4. Codiaceae. Compound Green Felts. Filaments 

 compacted into a large plant body ; isogamic ; marine. C odium, 

 PenicUlus, Udotea, Halimeda. (Pf. I, 2, 138.) 



Family 5. Vaucheriaceae. Simple Green Felts. Filaments 

 single, free ; heterogamic ; in fresh or brackish waters, or on wet 

 earth. Vaiicheria. (Pf. I, 2, 131.) 



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