670 Our Fresh- Water Alge. 
of reds and greens and olives. With the return to the interior the 
desire rises to expression, “ Would that the inland waters contained 
such treasures as these mosses of the sea!” It is the old story, the 
wish is father to the thought, and the thought will perchance come 
to you, that perhaps they do; why should there not be mosses in 
the lake and river, brook and clear spring, as well as in the brine? 
and you resolve to look for yourself on your return, or you ask 
some one who knows to tell you if there are not also alge in the inland 
waters. “ Yes, certainly,” he replies, and you then inquire, “ Why 
is it then that I have never seen them?” to be reminded in turn 
that it is not the first time the eye has been awakened to perception 
of the beauties round its home by travels in a foreign land. 
Besides, the algæ of fresh-water are smaller and less conspicuous 
than those of the sea; many are microscopic, and many others are, 
when taken singly, but just visible to the naked eye. They are less 
varied in color as well, and so it has happened that many collectors 
know the sea mosses first, and if knowledge of the algx of fresh 
water comes at all, it comes as a derivative from the other. 
To compare the actual organs of the alga and the flowering 
plant, we remember that the flowering plant is adapted to land- 
conditions, securing nourishment from the air by its leaves an 
from the soil by its roots. The alga is adapted instead to water 
conditions and has no leaves nor roots for procuring nourishment, 
but absorbs through its general surface. The alga may or may not 
have root-like bodies (rhizoids), or a root-like base (a dise or hold- 
fast), but if present, these are simply to fix the plant in position. 
Presence of distinct stem and branches is optional with either. Most 
flowering-plants produce leaves ; most alga do not; those leaf-like 
bodies which are produced, as by the Sargassum or Gulf-weed, are 
called phylloids; these do not occur in the strictly fresh-water 
species, As its name indicates, the flowering-plant is to produce - 
flowers, and from them seeds containing an embryo of one or more 
seed-leaves (cotyledons), Alga produce no flowers and seeds, but 
instead, as a usual rule, spores. Their spores resemble seeds a8 
appearance and in function, but contain no embryo and differ 12 
details of development. ‘The alga is thus the less specialized, sii 
more simple, the lower in the scale of creation. Instead of delega 
ting the functions of plant-life to separate portions of itself as | 
