174 
METHODS IN PLANT HISTOLOGY 
When possible, use the water in which the algae were growing, 
since very few take kindly to a sudden change of water. If the 
material has been brought to the laboratory in a very small quantity 
of water, fill the jar about two-thirds full with tap water. Let the 
water run for 2 or 3 minutes before you fill the jar, since the water 
standing in the pipes is injurious, or even fatal, to most algae. Add 
water occasionally, only a little at a time, to compensate for evapora¬ 
tion. If the water has evaporated until the jar is about one-third 
full and you fill it nearly to the top with tap water, you are likely 
to kill some of the most desirable forms. 
It is a mistake to put too much material into a jar. A wad of 
Spirogyra half as large as one’s finger is as much as should be put 
into a gallon jar. As it grows to ten or twenty times that amount, 
it is not necessary to keep throwing it out, since it will gradually 
accommodate itself to conditions. However, do not let the jar 
become choked with the material. 
Cultures may be started even in the winter. Bring in some mud 
over which algae were growing the previous summer or autumn; 
put it into a jar and fill it two-thirds full of tap water. Also bring 
in sticks, leaves, and stones from good alga localities and put them 
into jars of tap water. Cultures may be started either by taking 
mud and sticks from under the ice or by taking them from places 
which have entirely dried up during the summer or autumn. A 
few such jars will be likely to yield a variety of material. 
If you have a good jar of Oedogonium, or some other desirable 
form, do not throw it out if the alga should disappear. Remember 
that temporary disappearances occur in nature. Allow the culture to 
become dry and then set it aside where it will be protected from dust. 
After a few months, pour on tap water and it is very likely that you 
will soon have a good jar of Oedogonium. Many algae behave simi¬ 
larly; some, like Volvox, appear for a short time and then disappear for 
a long time; some, like Cladophora, may last the whole year and grow 
so luxuriantly that the excess material must be removed; and some, 
like Ulothrix, we have not been able to cultivate at all in the laboratory. 
Some very useful hints on collecting and growing fresh-water 
algae for class work will be found in an article by Dr. J. A. Nieuwland 
in the Midland Naturalist , 1:85, 1909. 
Professor Klebs has shown that various phases in the life-histories 
of many algae and fungi may be produced at will. By utilizing his 
