336 FRESH WATER SKETCHES. 
what he who runs may read, and armed with the microscope seek 
out new sources of pleasure in its wonderful revelations. 
The plants to which reference has been made, though in them- 
selves far from being microscopic, afford many points of interest 
to the microscopical botanist. In the Nymphzea, Nuphar and Lim- 
nanthemum, for example, are presented vessels of an unusual form, 
marked like the ordinary dotted ducts so common among land 
plants, but singularly branched in a manner quite unlike what is 
usually met with in the latter. These vessels may be easily seen 
in a thin slice of the stems of the leaf or flower, or they may be 
obtained completely isolated by letting portions of the plant mac- 
erate in a glass of water for a few days in summer, until partial 
decomposition has taken place, when the vessels in question may 
be easily picked out with the point of a needle and examined by 
themselves. In the pure limpid jelly which invests the younger 
. parts of the Water-shield (Brasenia peltata) is another object 
` which cannot fail to attract the attention of the botanical student. 
If this be examined under the microscope, it will be found that 
the plant is not surrounded, as it appears to the naked eye, by a 
mass of homogeneous unorganized jelly, but that it is covered with 
minute hairs, each one of which is the axis of a cylindrical mass 
of jelly excreted by itself. In the Pickerel-weed (Pontederia cor- 
data) an interesting subject of study may be found in the slender 
crystals (raphides) contained within the large ellipsoidal cells, of 
which this plant contains such great numbers, both the crystals 
and the cells being much like those which have been called 
“ Biforines” and which occur in Calla, Arum and other plants of 
the natural family Aracee. The true biforines when separated 
from the other tissues in water, rapidly discharge the crystals from 
one or both ends of the cells, and often with such force as to drive 
the cells backwards like a rocket, but this action is Rose 
wanting in the crystalline bundles of Pontederia. The 
phragms or thin plates of cellular tissue, met with in the stem si 
petioles of this plant will also be found to afford very beautiful 
objects for the microscope. 
The Water Lobelia (L. Dortmanna) is an interesting plant, 
oad recognized by its naked stem flowering above water, W. 
ts base is surrounded by a bunch of radical leaves reduced to 
mere petioles. This plant, like all of its tribe, has a milky juice, 
and the latex vessels in which it circulates may be found in the 
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