252 ALGiE. 



8. Laminaria. Frond coriaceous (rarely membranaceous) 

 plane, expanded, without a midrib. Fructification; seeds or 

 granules forming dense sori or spots, and imbedded in the 

 thickened surface of some part of the frond. Grev. 



Tribe IV. Sporochnide^e. Marine plants ; of an olivaceous or 

 yellowish-green colour, (iiot changing to black in drying) ; of a 

 cartilagineo-membranaceous substance, becoming flaccid almost 

 immediately on exposure to the air, in some cases, acquiring 

 under such circumstances, a verdigris-green colour, and then pos- 

 sessing the property of rapidly decomposing other delicate Alga; 

 in contact with them. Frond with a scutate (rarely tomentose) 

 root, flat, compressed or cylindrical, with distichous (rarely ir- 

 regidar) branches, and bearing, in most species, at some period 

 of their growth, little pencil-like deciduous tufts of fine green fila- 

 ments. Fructification ; so far as it is known, composed of club- 

 shaped, moniliform, radiating filaments, either forming sessile 

 warts, or arranged concentrically in little stalked, club-shaped 

 bodies, terminated by pencils of delicate fibres. Grev. 



9. Desmarestia. Frond cartilaginous, plane or compressed, 

 distichously branched, while young furnished with marginal de- 

 ciduous tufts of fine green filaments, the branches set with mar- 

 ginal spines. Grev. 



10. Dichloria. Frond cylindrical, filiform, cartilaginous, 

 pinnated with opposite branches and becoming flaccid and of a 

 verdigris-green colour on exposure to the air. Fructification 

 unknown. Grev. 



11. Sporochnus. Frond filiform, cylindrical or compressed, 

 cartilagineo-membranaceous. Fructification ; club-shaped, moni- 

 liform filaments, radiating in scattered warts, or concentrical in 

 distinct (mostly clavate, stalked) receptacles, often terminated 

 by a deciduous tuft of filaments. Grev. 



Tribe V. CHORDARiEiE. Marine plants, of an olive-green colour, 

 becoming darker on exposure to the air, of a cartilaginous and 

 lubricous substance. Boot scutate. Frond continuous, cylin- 

 drical, filiform, composed of a solid cellular centre and a dense 

 exterior mass of concentrical filaments. Fructification imper- 

 fectly known. Grev, 



12. Chordaria. Frond filiform, cartilaginous, solid, con- 

 tinuous, composed exteriorly of a stratum of concentrical fila- 

 ments. Grev. 



Tribe VI. DictyotevE. Marine plants, of an olive-green col- 

 our, not changing on exposure to the air, of a membranaceous, 

 flexible Rarely cartilaginous) substance and reticulated struc- 

 ture. Root either naked and scutate or composed of a mass of 



