(250 ) 
great, but it would be impossible to characterize them. The aim 
here has been to take a middle course. The wide view of species 
seems entirely untenable, but the effort throughout has been to make 
the segregations conservatively. Definite measurements are essen- 
tial to the descriptions and often afford valuable characters. But a 
Chara has but a few nodes and internodes, of necessarily different 
ages, and the upper ones almost always have different dimensions 
from the lower and more mature. The data given here are intended 
primarily to represent the latter, but also to include all parts which 
have assumed a quasi-final form. Much emphasis has been laid 
by others upon the size of the spore, and this is often a good char- 
acter. But spores, like other things, are of different sizes at dif- 
ferent ages, and it is extremely desirable to have perfectly mature 
material. Unfortunately it is often impossible to tell whether a 
spore is fully mature or not, as the final appearance is reached 
before it attains its full size. 
The observer should guard against another source of error. Be- 
sides the normal sporocarps there are found in many species others 
of a different shape, usually nearly globular except for the crown- 
cells, the odspores yellow or orange in color, often glistening, and 
crowded with starch. Their true significance is not clear, but they 
afford no characters of systematic importance, except that as a rule 
the crown-cells resemble those of the normal sporocarps, and the 
striae upon the odspore, though fainter, seem to be of the typical 
number forthe species. Odspores which are either globular or yellow 
should be viewed with suspicion. A few species in other respects 
quite distinct are here described with such odspores. In these 
cases it is believed that although the species will prove good, and 
can be recognized by the vegetative characters, the description wil 
require future emendation. The brown oéspores of some of the 
best-known species are not to be confused with the yellow ones 
above mentione 
The most plaucible explanation of the name Chara is that it was 
used in ancient times in southern France and northern Italy for Ca- 
rum and other allied plants. From the resemblance of its whorled 
leaves to the inflorescence of the umbellifers, the true Chara was 
first included, and now monopolizes the name. It is much more 
often said to be a literal rendering of, the Greek yapd, joy or 
delight, supposed by some to indicate their fondness for water, by 
others their effect when observed by the eye alone; others connect 
