258 ALGiE. 



47. Ulva. Frond membranaceous, of a green colour, plane 

 (in some cases saccate, and inflated in a young state). Fructi- 

 fication ; minute granules, mostly arranged in fours. Grev. 



48. Tetraspora. Frond tubular or inflated, gelatinous. 

 Fructification; minute granules, loosely arranged in fours. 

 Ag. 



49. Enteromorpha. Frond tubular, hollow, membran- 

 aceous, of a green colour and reticulated structure. Fructifi- 

 cation ; three or four roundish granules, aggregated in the reti- 

 culations. Grev. 



50. Bangia. Frond flat, capillary, membranaceous, of a 

 green, reddish or purple colour. Fructification; granules ar- 

 ranged more or less in a transverse manner. Grev. 



Tribe XII. Siphoned. Plants found in the sea, in, fresh 

 water or on damp ground, fyc, of an herbaceous green colour. 

 Frond either composed of membranaceous, filiform, continuous, 

 simple or branched tubes, or formed of a combination of similar 

 tubes, and then presenting a lax spongy body of various forms, 

 crustaceans, globular, cylindrical or fiat. Fructification; vesi- 

 cles (coniocystse, Ag.) produced on the outer surface of the tubes, 

 filled with a "darh-green granular mass: (in Botrydiuni,)l/ii entire 

 plant is little more than a hollow green globule with a radicating 

 tuft of fibres, whose fructification is unknown. Grev. 



51. Codium. Frond spongy, dark-green (crustaceous, glo- 

 bular, cylindrical or flat), composed of an interwoven mass of 

 tubular continuous filaments. Fructification ; opaque vesicles, 

 attached to the filaments near the surface of the frond. Grev. 



52. Bryopsis. Frond membranaceous, filiform, tubular, cy- 

 lindrical, glistening, branched, the branches imbricated, or dis- 

 tichous and pinnated, filled with a green minutely granuliferous 



fluid. Grev. 



53. Vaucheria. Fronds aggregated, tubular, continuous, 

 capillary, coloured by an internal green pulverulent mass. 

 Fructification ; dark-green homogeneous vesicles (coniocystae, 

 Ag.) attached to the frond. Grev. 



54. Botrydium. Plant a sphserical vesicular receptacle, 

 filled with a watery fluid, dehiscent at the apex, terminating 

 below in a radicating tuft of fibres. Grev. 



Tribe XIII. Lemanie.e. Aquatic plants, existing in fresh 

 and rapidly running water. Fronds slender, tubulose, either 

 whorled with papillce or monili form, formed of a coriaceous cellu- 

 lose membrane, the cells regular, interspersed with intercellular 

 ducts. From scattered points obscurely conspicuous, even exter- 

 nally upon this membrane, but on its interior surface, there 



