10 CHARA. 
which usually supplies the evidence for the existence of these 
plants in rocks of various ages, is too imperfect to enable us to 
decide accurately whether the fragments should be referred to 
Chara, Nitella, or other genera of Characee. 
In view of this difficulty it is better, therefore, to describe all 
the Characeous “fruits” by the term Chara, if we regard the 
generic name, when applied to fossils, rather in the sense of a 
representative of a family than of the genus Chara as defined in 
the more recent works on this anomalous group. 
We frequently find the statement that the oldest known fossil 
Charas are those which have been found in beds of Muschelkalk 
age from Moscow; but in no case have I been able to discover a 
reference to the author who first noted this occurrence. It is by 
no means improbable that we must go much farther back in the 
geologic series to find the earliest traces of Chara “fruits.” In 
a paper in the American Journal of Science for 1889, Knowlton* 
gives three figures of some ‘‘ problematic organisms’? which it is 
difficult to believe can be anything but Chara oogonia. They are 
described as minute spirally-grooved bodies 1:50 mm.—1°80 mm. 
long, and 1:70 mm. broad, with a small aperture at one end; these 
bodies occur in large numbers in Lower Devonian-Carboniferous 
sandstones, and were mentioned in 1878 by Meek,” who spoke of 
them as showing all the external characters of Chara. Knowlton 
recognizes the strong likeness to this genus, but quotes various 
opinions which throw a good deal of doubt on the plant-nature of 
these small fossils. One objection is that the fossil bodies have on 
their surface the marks of more than five cells, the number making 
up the envelope of recent Chara oospores; and in the living forms 
these spirally-placed cells are twisted to the left, but in the fossils 
to the right; this, however, Knowlton suggests is ‘‘no vital 
objection to the supposition that this might have been an archaic 
or original type from which the more modern forms have 
developed.” ® 
Other arguments against their Characeous affinities are (i) the 
1 T am indebted to Mr. Davies Sherborn for calling my attention to this paper 
and to Ulrich’s genus Moellerina mentioned below. Amer. Journ. ser. iii. vol. 
XXXVi. p. 202. 
* Report Geol. Surv. Ohio, vol. i. pt. ii. p. 219. 
3 Loe. cit. p. 204. 
