ALGM. 165 



73. CALOTHRIX. Filaments short, tufted, green or purple, 

 simple or pseudo-branched. 



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

 long, flaccid. 



75. OSCILLATORIA. Filaments rigid, acicular, radiating and 

 oscillating from a slimy stratum. 



TRIBE XX. ULVACEJE. Plants of a membranaceous or gela- 

 tinous substance and simple structure. Frond either a tubular 

 or flat, filiform or expanded membrane ; or a gelatinous amor- 

 phous mass ; or composed of an innumerable number of gela- 

 tinous globules ; hyaline, or, owing to the presence of fructifi- 

 cation, of a green, purplish, or pink colour. Fructification : 

 minute granules, which are either scattered through the frond, 

 or arranged in fours, or strung together in many moniliform y 

 filamentous series. 



# Plants membranaceous, not gelatinous. 



76. PORPHYRA. Frond foliaceous, purple. 



77. BANGIA. Frond linear, capillary, transversely dotted. 



78. ENTEROMORPHA. Frond tubular, hollow, simple or 

 branched, somewhat reticulated, green. 



79. ULVA. Frond foliaceous, membranaceous, green. 



* 4 Plants gelatinous. 



80. TETRASPORA. Frond gelatinoso-membranaceous, ex- 

 panded, green. Sporules in fours. 



81. PALMELLA. Frond a polymorphous, gelatinous mass, 

 filled with scattered granules (sometimes arranged in fours.) 



82. NOSTOC. Frond coriaceo-gelatinous, lobed, hollow or 

 solid, filled with curled moniliform filaments. 



83. PROTOCOCCUS. Plant consisting of aggregated minute 

 globules (filled with granules), and sessile on a gelatinous 

 mass. 



TRIBE XXI. BYSSOIDE.E. Plants of doubtful affinity, related 

 to the Fungi. Filaments articulated, hyaline, or coloured. 

 Fructification very obscure. They are found on rotten wood, 

 among mosses, on damp ground, on glass, or in chemical solu- 

 tions and other anomalous situations. 



84. BYSSOCLADIUM. Filaments arachnoid, radiating from a 

 centre, with scattered external granules. 



