234 THE VEGETABLE WORLD. 
from many species. The Fucacce are distinguished from all other 
seaweeds by a remarkable characteristic, namely, the position of 
their spores within little hollows sunk in the substance of the 
plant, and communicating with the surface by a pore. 
Dr. Lindley divides the order of Fucacese into the three following 
sub-orders, each distinguished by their own peculiarities :— 
e€ upper joint, sometimes 
Frona mono, or pleis sephonous, without : and 
nO , H ‘) Including Hydrogastrum 
bark, the utricles forming a lateral branchlet, Sell 7 Ectocarpus, 
I, VAUCHERLE. = A - . pa Dasy sanggpoa | or 03, 
fro west. 2 
Frond polysiphonous, barked and jointed, ‘. 
{ . q } ¢ Léeha £. A i Dictyosiphon, Laminaria, and Sper 
lor in heaps. } achnus. 
I. H neluding the Spacelaria, the 
. ULYSEREAZ 
Frond polysiphonous, often bladdery, vesi- ; 
cles seated in hollow conceptacles formed of Including the Lemanea, Phe 
Ill. Fuces, a folding-in. of the fold, pierced by a spore }Cystoceira, Sargassum, 
surrounded by flock; conceptacles scattered | naria, and Scirococcus. 
or collected upou a receptacle. 
Two species of Sargassum, S. vulyare and 8S. vacciferum, are 
frequently found on our shores as far north as the mouth of the 
Clyde and the west coast of Scotland; but they are mere waifs 
and strays cast with other tropical productions on our shores- 
They are the “Gulf-weed” which form floating meadows an the 
midst of the ocean. ‘ Midway the Atlantic,” says Maury, his 
‘« Physical Geography of the Sea,” p. 88, “in the triangular space 
between the Azores, Canaries, and the Cape de Verd Islands, 38 
the great Sargasso Sea, covering an area equal in extent to = 
Mississippi Valley; it is so thickly matted over with the 5 
weed that the speed of vessels passing through it is often retarded. 
When the companions of Columbus saw it, they thought it marked 
the limits of navigation, and became alarmed. To the eye, at® 
little distance, it seems substantial enough to walk upon.” ety 
reproductive bodies of these plants are in the beginning little yoo: 
ike bodies, invested by a very thin membrane, placed close over e 
inner sac filled with green granules. The spores are external ; tha 
is, they are inserted on the surface of a vescicle upon which they 
are generated. 
VAUCHERIA. 
Tufts of Vaucheria are formed of a network of cylindrical fila 
ments, branching and continuous, enclosing green granules and 
a colourless mucilage. This small plant, common enough 1 
marshy places, is rendered very remarkable by its diverse 
