EQUISETITES. 23 
Genus EQUISETITES, Sternberg. 
[Flor. Vorwelt, vii. 1838, p. 43.] 
A general name applied to such fossil remains as closely resemble 
the recent genus Eyuisetum. 
Brongniart,' Schimper, and other authors use the term Hyuesetum 
for the fossil representatives of that genus; as the former has 
pointed out, there are several species which from the character 
of the fertile as well as the sterile stem structures cannot be 
separated from the recent genus. So far as we are able to judge, 
this appears to be the case; but as yet we are in the dark as to the 
histological structure of the fossil forms, and, with such material 
as paleobotanists have to deal with, there cannot be any certainty 
as to the exact connection between the living and fossil equise- 
taceous plants. In addition to this necessary imperfection of the 
fossil material, there is another argument in favour of some slight 
distinction in the name used for species other than those now in 
existence, namely the fact that we thus have a convenient distin- 
guishing mark between recent species of Lguisetwm and their 
geological representatives. 
Owing to the absence of internal structure in the fossil repre- 
sentatives of the Hyutsetacee our exact knowledge of the ancestral 
forms of Equisetum leaves much to be desired. Graf Solms has 
called attention to this fact in his ‘‘ Fossil Botany,’’? and he gives a 
short critical account of the geological history of the sole surviving 
genus. A few examples have been recorded from the Coal-Measures 
of different countries, but as a rule there is very little to be learnt 
from them. Without attempting any review of the older equi- 
setaceous plants, it is of interest to note that there appears to be 
some evidence for the existence of this family in Britain during the 
Coal-Measures period. Kidston* has recently figured and described 
part of a sporangiferous spike which seems to resemble the fertile 
apex of a recent Eyguisetum stem. This new species from the 
Coal-Measures of Yorkshire is named Equisetum Hemingway. 
1 Brongniart, Tableau, p. 46. 
3 is WG. 
3 Annals, vol. ix. ser. vi. 1892, p. 138. A Permian species, Z. Vawolyi, has 
recently been recorded by Professor Zeiller from Commentry. (Saporta, Rev. 
gen. bot. vol. v. 1893, pl. ii. p. 179.) 
