34 EQUISETITES. 
In Figs. 3 and 8* we have examples of more perfect tubers. 
The tubers figured by Dunker under the name Carpolithus sertum 
agree very closely with some of the English specimens; but the 
absence of any definition of the North German species prevents 
us adopting Dunker’s name, even if we regard his specimens as 
identical with ours. 
In his second Memoir on the Wealden Flora, Schenk has figured 
a specimen with numerous tubers under the name Lyuisetites 
Burchardti, Dunk.; this seems, however, to have a closer resem- 
blance to our new species; the tubers are narrow and less spherical 
than those of #. Burchardti. If we compare Schenk’s fig. 1, 
pl. xxl. Paleeontographica, vol. xix. and fig. 1, pl. xxvi. Paleon- 
tographica, vol. xxiii. we notice a distinct difference, not only in the 
shape of the tubers, but in the general habit of the tuber-bearing 
plant. Schenk’s latter figure shows some of the tubers joined end to 
end; the same kind of arrangement occurs in some of the English 
examples, e.g. V. 2365a. It is, perhaps, not entirely satisfactory 
to have to rely upon certain differences in the shape of tuberous 
internodes in determining specific definitions; but in the present 
instance the available material appears to show well-defined 
differences, and there is confirmatory evidence in the fact that 
the two forms of tubers are never found in close association. 
V. 2871. Fig. 2. Internodes 1-1:2 em. long, about 2 mm. 
broad. The sandstone matrix is penetrated by stems and root 
fragments; portions of tubers. Cf. #. Burchardti, Dunk., pl. i. 
fig. 5. Eeclesbourne. Beckles Coll. 
V. 2871. Fig. 3. A few well-preserved tubers; two shown 
in place at one node; fragments of roots. Nodes not clearly 
marked, no ribs on the internodes, the latter about 1 cm. in 
length. Ecclesbourne. Beckles Coll. 
V. 2335. Fig. 8*, p. 33. Numerous tubers, some attached to 
the slender stem. Ecclesbourne. Rufford Coll. 
V. 727. Several tubers, with stem fragments; many of the 
former show surface depressions due to shrinkage of the tuber 
tissues. Ecclesbourne. Dawson Coll. 
V. 2865. Five specimens. No detail shown. Ecclesbourne. 
Rufford Coll. 
