alg;e. 257 



Fructification ; minute, aggregated capsules, surrounded by an 

 involucre. Grev. 



Tribe X. Gastrocarpe.e. Plants all marine, with a scu- 

 tate root, of a pink, red, or purplish-red colour, most of them 

 not changing much on exposure to the atmosp/iere, of a 

 carnose, gelati no-cartilaginous or gelatino-membranaceous sub- 

 stance ; the structure consisting of a cellular external coat 

 or membrane, and a pellucid, gelatinous, internal mass, mostly 

 traversed by colourless jointed filaments arising from the outer 

 membrane. Frond cylindrical, compressed or flat, continuous, 

 destitute of midrib or veins. Fructification; roundish clusters 

 or globules of red seeds, imbedded in the internal gelatinous sub- 

 stance of the frond, and often unaccompanied by an external 

 pore. Grev, 



42. Irid.ea. Frond flat, expanded, carnose or gelatino- 

 cartilaginous, more or less of a purplish-red colour. Fructifica- 

 tion ; globules of roundish seeds, imbedded between the two coats 

 of the frond. Grev . 



43. Halymenia. Frond nearly flat or cylindrical, gelatino- 

 membranaceous, of a pinky-red colour, more or less di- 

 chotomous, the segments often laciniated. Fructification; puncti- 

 form globules of seeds, imbedded in the central substance of the 

 frond. Grev. 



44. Dumontia. Frond cylindrical, simple or branched, 

 membranaceous, tubular, gelatinous within, of a red or purple- 

 red colour. Fructification ; globules of seeds, attached to the 

 inner surface of the membrane of the frond. Grev. 



45. Catenella. Frond filiform, somewhat compressed, 



creeping, throwing np numerous branches, contracted, as if 



jointed, in a moiiiliforin manner, composed internally of branched 



filaments radiating from the centre. Fructification unknown. 



(in r. 



Tiube XI. Ulvaceje. Plants J]>,ntd in the sea, in fresh-water 

 or on damp ground) fyc, of an herbaceous gran or fine purple 

 colour, (fa thin fender membranaceous substance and reticulated 

 structure, rarefy gelatinous, Frond with a very minutely scu- 

 ta t< root, expanded, or tubular and continuous. Fructification; 

 roundish and mostJij r/uatcrua/c r/ranules or minute sporular 



grams, imbedded i„ tin dlicate me m b ran e (if the frond. (,',, r. 



46. PoRpnrfiu. Frond plane, oneeediagly thin ami of a 

 purple colour. Fructification; 1. Mattered tori of orsl seeds t 



— l\ roundish granule*, mostly arranged in a quaternate manner, 



ami Covering the whole frond. (,'rn . 



s 



