Vaucheria 79 
VAUCHERIA. 
F. M. ANDREWS. 
In Vaucheria the branches are rather long in proportion to the 
main part of the plant in some cases, and in other instances rather 
short in this respect. The plant branches at various angles. In most 
of the species of Vaucheria in the vegetative parts this is less than a 
right angle as regards the facing surfaces of the main filament and its 
branch. A reproductive branch generally starts off at right angles to 
the main filament and can be recognized as a branch that will produce 
reproductive organs on this account. They may become at times some- 
what less or greater than a right angle, according to circumstances. 
The irregular branching is conspicuous in all the different species 
of Vaucheria except one. This exception is seen in Vaucheria tuberosa, 
which branches dichotomously. The single tubular cell which is often 
much elongated may sometimes reach a length of 30 cm.” The water 
forms are generally longer than species that are to be found growing 
on the soil and in many cases also of a coarser nature. Since it grows 
frequently in tufts, especially the forms in running water, the length 
and extensive branching of the mass is often not at first so evident. 
In the formation of the large zodspores the end of the filament is 
cut off from the rest of the plant by a transverse wall. After a time, 
depending on conditions, the contents of the single large cell thus formed 
rounds itself and later escapes through the end of the cell as a single 
large zodspore. Sometimes attempts to cause these zodspores to form by 
flooding the plants with water, as in the case of the land forms, is 
very successful, but at other times this process is not attended by very 
great success or none at all. 
The function of the above-mentioned large cell to form the large 
zoospores which will reproduce the plant asexually, even though formed 
in the usual way, does not always do so, owing to changed or unfavor- 
able conditions. Instances of this kind can occasionally be seen in plants 
that have been submerged. One unusual instance was observed by the 
writer as is shown by the accompanying Figure 1. The terminal cell, 
which was cut off in the usual way, was of normal size and shape and ap- 
parently was vigorous in every respect as was the rest of the plant. 
The figure here given was drawn by the aid of a camera a short time 
after the specimen was observed, from fresh material which had been 
gathered one hour before. 
The unusual feature about this cell was the production of two 
branches from the sides. These branches were probably of different 
ages, as both seemed to have had equal opportunity for growth. It 
will be seen, however, that the branch nearest the apex of the cell is 
longer than the one near the base of the cell and near the transverse 
1 Sachs, J., Lehrbuch der Botanik. Vierte Auflage, 1874, p. 273. 
2 Sachs, J., I. ¢., p. 273. 
