ORDERS ANT) GENERA. XI 



XC. Vaucheria. Filaments free, dichotomous or irregular. 



Order 15. Confervace.*:. Green, marine, or freshwater Alga, composed of 

 articulated filaments, simple or branched, free or invested by gelatine. 

 Cells cylindrical, truncate. 



Sub-order 1. ConfervEjE. Filaments free, destitute of gelatine. 



XCI. Cladophora. Filaments tufted, branched. 



XCII. Rhizoclonium. Filaments decumbent, subsimple, emitting a few root- 

 like branches. 



XCIII. Conferva. Filaments unbranched. 



Sub-order 2. Ch.etophore.e. Filaments united in submembranaceous or 

 gelatinous fronds ; cells often tipped with bristles. Sporangia external. 



XCIV. Ochloch.ete. Frond disciform. Filaments radiating from a central 

 point, prostrate, irregularly branched ; each cell produced above into a 

 rigid, inarticulate bristle. 



Order 16. Ulvace.e. Green, or rarely purple, marine or fresh-water Algre, 

 composed of small polygonal cells, forming expanded membranes, or mem- 

 branous tubes ; very rarely arranged in filaments. 



XCV. Enteromorpha. Frond tubular. 



XCVI. Ulva. Frond flat, green. 



XCVII. Porphyra. Frond fiat, purple. 



XCVIII. Bangia. Frond filiform (mostly), purple or pink. 



Order 17. Oscillatoriace/E. Green or blue, rarely purple, marine or 

 (more frequently) fresh-water Alga, composed of continuous, tubular, 

 simple, or rarely branching filaments, which are either free or j 

 with gelatine. Endochrome cumulated, at length separating into lenti- 

 cular sporidia. 



Sub-order 1. Rivularie^e. Filaments united together into a solid gelatinous 

 or cartilaginous frond . 



XCIX. Rivularia. Filaments not sheathed. 



C. Sciiizosiphon. Filaments sheathed; the sheath multifid. 



Sub-order 2. Oscillatorik I / luffed or stratified, free. 



CI. Schizotiirix. Filaments rigid, in branching bundles, at length splitting. 



CII. Calothrix. Filaments short, tufted, fixed at the base only. 



CIII. Lyngbya. Filaments elongate, decumbent, flaccid. 



CIV. Microcoleus. lUaments needle-shaped, several enclosed together in 

 membranous or gelatinous sheaths. 



CV. Oscillatori \. Filaments needle-shaped, straight, or slightly carved, short, 



In aped together in gelatinous strata, oscillating. 



< VI. SriKi l.i \ a. Filament* spirally twisted, lying in a niueou- stratum, vividly 

 oscillating. 



Order 18. NOSTOCU \( i. l . G 'f-vater <>,• rarely mafimt . 



poseif qf moniliform filaments, lying in a gelatinous matrix. Cells glo- 



■ or oral. 



CVI1. Monokmia. A single filament enoloeed in a convoluted gelatinous ami 

 branching frond. 



