220 -CRYPTOGAMIA. 
ORDER III. 
ALGH.—SEA WEEDS, &c. 
Alga, Juss.; he included in Algw the Lichenes, now made 
separate Order.—Hydrophyta, Rich.—Alg@ and Chetopho- 
roidee, Grev. 
Cuaracters.— Mostly aquatic vegetables, growing in the 
sea or in fresh water, destitute of a root for absorbing now 
rishment, but often firmly fixed by a fibrous or callous base, 
called a scutate root. Substance gelatinous; thin, membra-— 
nous, or pellucid ; tough and horny ; or even woody. B ronds 4 
‘sometimes arising directly from the root, and constituting 
the whole plant; at other times placed on a stem (stipes, 
more or less thick ; composed of delicate capillary filaments 
often finer than hair, of thin membranous bands ‘varying 
in length and in breadth, or of a more solid cylindrical or 
strap-like substance ; sometimes solid, at other times tubular 
frequently divided by joints or articulations; and often 
flated at particular parts, forming vesicles filled with air. 
_Sporules imbedded in tubercles in the substance of the ver 
_ getable ; in simple dilatations or projections arising fromthe 
_ frond; scattered on its surface; placed in the tube when th 
_ frond is tubular; surrounded by an open involucre; oF 
_-__ elusters on a common receptacle. | Semitransparent, and © ; 
eos a brown, green, purple, or reddish colour. ‘* After having 
been kept dry for a considerable length of time they will 
a revive by immersion in water ; but that portion of the plant 
only imbibes the fluid which is immersed in it.—Hooker- 
Examptes.—Bladder Fucus, Sea Ware, or Sea Wraek | 
(Fueus vesiculosus) ; Dulse (Fucus palmatus ; Rhodomem@ 
palmata, Grev.; Halymenia p., Hooker); Tangle (Fucus 
digitatus ; Laminaria digitata, Hook. and Grev.); and al) 
er Sea Weeds. The green slimy matter observed ver? 
