2 . Uuivcrsity of California Publications i)i Botanij [Vol.8 



PAGE 



Subfamily 3. — Lj-ngbyeae 67 



17. Phormidium 68 



IS. LyiiKbya 72 



19. Plcctonema 78 



20. Symploca 80 



Subfamily 4. — Schizotricheac 83 



21 . Hydrocoleum 84 



22. Microcoleus : 85 



Suborder 2. — Heterocj'stineae , > 89 



Family 4. — Xostocaceae 89 



23. Anabaena 90 



24. Nostoc 92 



Family 5. — Rivulariaceae .■ 93 



25. Calothrix ■. 94 



26. Dichothrix 103 



27. Isactis 104 



28. Rivularia 105 



Family 6. — Stigonemataceae 109 



29. Mastigocoleus 110 



30. Brachytrichia Ill 



Literature cited 113 



Subclass I. MYXOPHYCEAE stiz. 



Thallophytes of simple construction possessing a blue coloring 

 matter, known usually as phycocj^anin, in addition to the chlorophyll ; 

 plants unicellular, or in colonies of regular or irregular form, or in 

 longer or shorter, simple or branched filaments ; cells discoid to 

 globular, cuneiform or variously shaped, possessed of a distinct but 

 very thin cell wall, a protoplast differentiated into a central chromatin 

 containing body (nucleus, but without membrane) and outer color 

 containing layer (cytoplasm and chromatophore?) ; granules (reserve 

 materials?) of various kinds generally found in the cells, often 

 arranged very definitely as regards certain cell walls ; cells whether 

 single, in colonies of regular or irregular form, or in filaments com- 

 monly surrounded by a more or less ample tegument of gelatinous to 

 cartilaginous consistency, colorless or of various shades of yellow, 

 brown, red or purple, structureless or stratified in various ways, com- 

 monly in the form of a "sheath" in the filamentous forms, the sheath 

 enclosing one to several or many rows of cells (or trichomes). Multi- 

 plication: (1) by cell division, separating single cells (coccogonia) 

 or short filaments (hormogonia) ; (2) by spores, either formed within 

 a cell (gonidangium) in larger or smaller numbers (gonidia) or by 

 diffc'rentiation as to size, shape and contents, and the formation of a 

 thick outer coat (resting spores) ; sexual reproduction unknown. 



