alg.i:. 251 



Receptacles cylindrical, more or less lanceolate, tnbercnlated, 

 terminal. Seeds in distinct cells. Grev, 



3. Halidrys. Frond compressed, coriaceous, linear, pin- 

 nated with distichous branches. Air-vessels lanceolate, stalked, 

 divided by transverse septa. Receptacles lanceolate, stalked, 

 compressed. Seeds in distinct cells. Grev. 



4. Fucus. Frond plane, compressed or cylindrical, linear, 

 dichotomous, coriaceous. Air-vessels, when present, innate in 

 the frond, simple, large. Receptacles terminal (except in F. 

 nodosus), turgid, containing tubercles imbedded in mucus, and 

 discharging their seeds by conspicuous pores. Grev. 



5. HlMANTHALlA. Frond coriaceous, orbicular, peziziform. 

 Vesicles none. Receptacles elongated, strap-shaped, compressed, 

 dichotomously divided, springing from the centre of the frond, 

 containing immersed tubercles, furnished with a pore. Grev. 



Tribe II. Lichixe^. Marine plants, of a blachish-green co- 

 lour changing to deep blach on exposure to the air, of a cartila- 

 ginous substance and fibrous texture. Frond flat or cylindrical, 

 minute, branched in a dichotomons or subpalmated manner. 

 Fructification terminal or nearly terminal, composed of capsules 

 furnished, with a pore and fiMed with a colourless gelatinous 

 mass of very fine filaments, among which pellucid oral or oblong 

 seeds are disposed in many radiating moniliform str'ns. Grev. 



(i. Lichina. Frond cartilaginous, blackish- green, dichoto- 

 mous. Fructification ; roundish capsules of the same colour as 

 the frond, containing radiating moniliform lines of pellucid seeds, 

 imbedded in a gelatinous mas> of filaments. Grev, 



Tribe III. Laminabie-e. Marine plants, of an olive-brown 

 or olive-green colour, becoming somewhat darker on exposure to 

 tin mi\ varying in texture from coriaceous to membranaceous. 



Frond with <i lobed or fibrous root, more or less stipiiote and 



forming <> plum, entire or cleft expansion, in >< fur cases fur- 

 nished with (oie er mmc ribs. Vesicles <> we, {except in the 

 c genus Macrocystus,) unless the hollow stem oft 



In e, nsid n d as such, Fructification, so for os is hitherto known, 



either seeds mixed with " moss of vertical, jointed filaments, o> 

 roundish granules, without filaments, forming, in both easts. 

 dense, spreading spots or tori, on tin suh part of 



the frond, Structun densely fibroso-ceUular, without any ap- 

 pearance of reticulation. Grev, 



7. A i. \ i:i.\. Frond membranaceous, furnished with m per« 

 current, cartilaginous midrib; the st< m pinnated with distinct 

 leaflets. Fru tifi* pj iii«»i m d in 



the ii' i 



