THE FARM STREAM 
the swiftest current, or trailing down the 
ledges in the waterfall, or encircling the 
piling where the waves wash it constantly. 
It is of a bright green color. There are apt 
to be various other algse also, some forming 
spots and blotches of blue-green color on the 
surfaces of rocks, where partly exposed at low 
water, and others forming little brownish 
gelatinous lumps like peas lying on the 
stream bed. Of the higher plants there will 
be hardly any present in the rapids: per- 
haps, a few trailing mosses or other creepers 
rooted in the crevices at the edge of the cur- 
rent, and just escaping annihilation at every 
flood. 
In quiet waters covering muddy shoals 
the vegetation is richer and more varied. 
The dominant plants are seed plants. 
Some of these (such as are shown in Figs. 12 
and 13) grow wholly submerged. Afew grow 
rooted to the bottom, but have broad 
leaves (Fig. 14) that rest wpon the surface. 
35 
4 
Fic. 13. Leaf-form 
in three common sub- 
merged plants whose 
leaves grow in whorls 
surrounding the stem 
at the nodes: a, the 
common water-weed 
(Elodea canadensis or 
ig alee canadensis); 
6, the water horn- 
wort \Ceralotheliem 
demersum); the 
water milfoil (itsrio- 
phyllum). 
A few small plants (Fig. 15) float freeupon the surface in the 
more sheltered openings. 
And there are many rooted in the 
Fic. 14, Outlines of four common kinds of floating leaves: a, the floating river- 
weed (Potamogeton natans); b, the spatter-dock (Nymphaea advena); c, the white water- 
lily (Castaillia odorata); d, the water shield (Brasenia peltata). 
