Sai pba UV An tale ele a 
FRESH WATER SKETCHES. 839 
tubes which closely envelop it. It contains numerous starch glob- 
ules and is capable of germination. These nucules when ripe are 
quite hard and not being readily decomposed are often met with in 
a fossil state in fresh-water deposits. Lamarck mistook them for 
the shell of a mollusc and called them Gyrogonites. The granule 
differs much from the nucule. Its exterior presents a number of 
triangular plates with radiating cells and indented edges. Each 
one of these plates supports in its interior a cluster of fine artieu- 
lated threads, in each joint of which is coiled up a spiral cileated 
filament. Upon the bursting of the globule, these filaments (sper- 
matozoids) escape into the water, where their wonderfully active 
movements have led to their being looked upon as true animal- 
eules. They are, however, merely agents in the fertilization of the 
germ-cell, and are analogous to the singular bodies discovered by 
Meyen in the antheridia of mosses. 
The Nitella (Chara) presents such curious phenomena that it 
is certainly worth the trouble of keeping it, and nothing is easier 
than to effect this. Each cell of the plant seems to have its own 
independent life, so that if any portion of the plant be thrown 
into a glass of water with a little pond mud, it will continue to 
grow and flourish. “I have sometimes known it in winter to 
separate at its joints, so as to give a number of completely 
isolated cells, each one of which continued alive all winter, dis- 
playing the ordinary circulation, and in the spring developing 
a whorl of new joints.” * 
Another plant also easy of cultivation is the Water-tape ( Vallis- 
neria spiralis L.) which shows the circulation not less beautifully 
than does the Nitella. This plant grows in immense quantities on 
the flats in the Hudson River, and sometimes to such an extent as 
to afford a serious obstacle to the passage of a boat. Its singular 
mode of fecundation is thus described by Dr. Gray in his excel- 
lent “ Botany of the Northern States.”+ The staminate flowers 
being confined to the bottom of the water, by the shortness of the 
scape, the flower-buds themselves spontaneously break away from 
their short pedicels and float on the surface, where they expand 
and shed their pollen around the fertile flowers which are raised to 
the surface at this time; fertilization being thus accomplished, 
the thread-form fertile scapes coil spirally, and draw the ovary 
#3. W. Bailey. tp. 463. 
AMER. NATURALIST, VOL. V. 22 
