226 SEA-WEEDS. 
















little bodies containing definitely formed granules whid 
answer for seeds; and on these characters, varying in each 
genus, the study and arrangement of the several species to 
a great degree depends. It is obvious, then, that colored 
plates, or even dried specimens, would be of little value in 
determining our native species, unless something more than 
a mere comparison of their external aspect was made. 
The sea-weeds have no roots, many float upon the surfi 
of the ocean, and others, firmly affixed to the bottom or to 
stones and shells, are only anchored for security ; their nout- 
ishment being derived from the atmosphere, and from the 
water in which they are periodically or continually immersed. 
The narrow and threadlike, or it may be the broad ail 
thickened plant, equally consists of a frond, a word derived 
from frons (Latin), meaning leaf: this frond may be simple 
or undivided, or cut into many coarser or finer po 
sometimes with great beauty. The color of the frond 
usually either green, olive or black and red, varymg 
intensity, the most beautiful being the different shades 
red; those with the paler tints, or with yellow and 
being partially bleached and in an incipient stage of decay. 
What we notice in terrestrial vegetation as we #8% 
from the level of the sea to the summit of mountains, M 
belts or zones of plants, certain species growing only. 
tain conditions of temperature, we can find reversed w 
sea-weeds, the finer and more beautiful kinds growing 
in deep water, and where the temperature is uniformly 
and cold. Collectors of sea-weeds, accordingly, avail 
selves of the dredge, or of low tides, or of fieree storms, 
which latter agency the deep-water species, torn from 
bottom, are cast upon the shore. es: : i 
If we should visit the rocky coasts of Massachus 
Nahant, Swampscot, Marblehead, Cohasset, ete., 
should find the shallow pools made by the re 
filled with the following kinds of Algæ, which, as 
little noticed, may be worth looking at. 
