218 THE SEA-WEEDS AT HOME AND ABROAD. 
just so far inland, which the closely attached lichen defines by 
its persistence in bright yellow colors in the strict line of ter- 
restrial and maritime growth. They stand there patient senti- 
nels to denote that the floods shall no more cover the earth ; 
the lichen the earth's plant, and the alga the sea’s plant, 
approximate and almost kiss each other in approach. Noth- 
ing higher in the scale of organization ventures so near; not 
the sedge, bulrush or hardiest grass dare grow so close to the 
waves. Nor are lichen and alga far removed in consan- 
guinity ; in structural difference something; some more ex- 
posure to sun and rain, to snow and ice, to heat and cold, in 
existence and continued individual life vastly more in favor 
of the little crusted slow-growing lichen, patient, untiring, 
serenely beautiful, doing by day and night its usual work 
and breaking down the hardest and most obdurate rock 
formations by the gentlest persuasion of its constant pres- 
ence to aid the atmospheric influences. 
Tbe alge are so diverse in their forms, and so many in 
number, computing only the precise kinds or species, to say 
nothing of innumerable varieties, many of which have been 
separately and minutely described, that in orde: to facilitate 
the labor of finding out what they are it has been found best 
to divide them into three great groups known by the color 
of their seed-vessels. Butas it is not always possible to find 
their seed-vessels, or even those minuter parts which though 
not seeds serve for similar purposes, because like other plants, 
and what we call flowers or flowering plants, these too have 
partieular seasons of the year when they produce them, so 
to look for strawberries after the vines have done bearing 
would be precisely like looking for seed-vessels on sea-weeds 
when they had passed the season. Some kinds, too, like 
some other and higher plants never bear any seeds in our 
latitudes, but such seed bearing plants must be sought else- 
where. Fortunately in this dilemma the chances of success 
are in our favor, and the usual color of the sea-weed corres- 
ponds with the color of the seed it bears. The rosy or 
