260 OSCILLATOREJE. 



Hob. In the celebrated warm waters of Bath, spreading 

 rather unequally in broad velvet-like patches, of a dark 

 green colour : Rev. H. Dames. 



(t The irregularity of its appearance arises from the fila- 

 ments being collected together into little ascending tufts, 

 apparently rooted in the muddy deposit of the water. Each 

 tuft proves, on examination, to consist of simple uniform even 

 filaments, crowded together and quite pellucid, and equally 

 destitute of joints and branches : their diameter is not more 

 than the eighth or tenth thousandth part of an inch." Sm. 



30. MICROCOLEUS Desmar. 



Char. Filaments simple, straight, brittle, closely striated, in 

 bundles, and enclosed within broad, membranous, and 

 branched sheaths, from the apices of which they protrude. 



Chthonoplastus Kiitzing, Phyc. Gener. p. 197. 

 Derivation. From pucpos, small, and KO\SOS, a sheath. 



This is an exceedingly beautiful and interesting genus ; the 

 younger branches or sheaths usually enclose but two or three 

 filaments, while the older contain as many as fifty or sixty : 

 it is difficult to conceive in what way the filaments become 

 multiplied within the sheath, unless it be by a longitudinal 

 division of them. 



1. MICROCOLEUS REPENS Harv. 

 Plate LXX. Fig. 3. 



Char. Fronds terrestrial, decumbent, radiating, branches diverg- 

 ing, curled and twisted, gradually tapering to the extre- 

 mity. Filaments large. Striae subdistant, evident. 



Oscillatoria chthonoplastes ft Harv. in Hook. Br. Fl. ii. 

 p. 373. Oscillatoria repens Ag. Syst. p. 61. Conf. 

 vaginata, Eng. Bot. t. 1995. Vaginaria vulgaris Gray, 

 Br. Fl. i. p. 280. 



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