260 AI.GM. 



hyaline pericarps ;— 2. roundish, gelatinous, involucrated re- 

 ceptacles, including mimute granules. 



64. Calithamnion. Filaments mostly pinnated, dissepi- 

 ments hyaline. Fructification; — 1. scattered capsules with 

 hyaline pericarps; — 2. polymorphous receptacles, containing large 

 granules. 



Tribe XVI. Conferve;e. Plants green, very rarely pink or 

 brown. Fructification {except in Bulbochaete) a granular 

 coloured internal mass (called endochrome) which affects vari- 

 ous forms. — Fresh-ivater or marine. 



65. Bulbochjete. Filaments branched, each articulation 

 bearing a deciduous inarticulate seta, fixed by a scutate base. 



66. Conferva. Filaments simple or branched, articulated, 

 uniform. Fructification; a granular internal mass filling the tube. 



67. Hydrodictyon. Filaments forming a net-work witli 

 regular polygonal meshes. 



68. Mougeotia. Filaments simple, finally united by trans- 

 verse tubes. Endochrome uniform, granular. 



69. Tentaridia. Filaments simple, finally united by trans- 

 verse tubes. Endochrome bipinnate. 



70. Zygnema. Filaments simple, finally united by transverse 

 tubes. Endochrome forming spiral rings. 



Tribe XVII. Oscillators. Plants green or brown, rarely 

 purple, continuous, tubular, seldom branched, though often ag- 

 glutinated together so as to appear branched. Fructification ; an 

 internal mass divided by transverse septa, which finally separates 

 into roundish or lenticular sporidia. — Fresh-water, marine, or 

 on damp ground. 



.71. Stigonema. Filaments cartilaginous, branched, marked 

 with transverse dotted rings. 



72. Scytonema. Filaments brown, truly branched, flaccid, 

 tough. 



73. Calothrix. Filaments green or purple, short, erect 

 simple or pseudo-branched. 



74. Lyngbya. Filaments green or purple, decumbent, very 

 long, flaccid. 



75. Rosaria. Filaments contracted at regular intervals ; 

 hades bipartite. 



76. Oscillatoria. Filaments rigid, acicular, radiating and 

 oscillating from a slimy stratum. 



