EQUISETITES. 3l 
follows! :—‘‘ Radicibus tamen glandium simile oliquid sepe adheret, 
quot porcos credas requirere.” De Candolle in his ‘‘ Flore Fran- 
caise ” * describes a new species, /. tuberosum, previously proposed 
by Hectot, and specially characterized by the formation of tubers 
on the lower nodes. In 1828 Bischoff’ figured the tubers of 
LE’. arvense attached to the rhizome. Among more recent authors, 
in addition to Duval-Jouve, Milde‘ gives figures of tubers attached 
to E. hiemale, L. 
Such tuberous internodes seem to have been unusually numerous 
on the rhizome of Eyuisetites Burchardti, as is clearly shown by 
the large numbers of attached and separate tubers in the English 
Wealden beds. No other species of yuisetites affords such 
numerous examples of tubers as this Wealden form, but a Tertiary 
species, Hyuisetites Parlatorii, Heer,®? should also be quoted as 
characterized by its chains of elliptical tubers. Heer originally 
described this species as Physagenia Parlatorii,® from Switzerland, 
and recognized a probable relationship to #. Burchardti; he in- 
cluded it, however, among the ‘‘ Plantae incerte sedis,” and, at the 
same time, compared the “bladders” to the tubers of Eyuisetum 
arvense, L., and other species. Schimper afterwards changed 
Heer’s name, Physagenia Parlatorii to Equisetum Parlatorii.’ 
Another instance of fossil tubers is recorded by Heer from the 
Jurassic beds of Amur,® under the name Lguisetum Bureense, 
Heer, and compared by him to the Wealden Lywisetites Bur- 
chardtt. The same author has recorded another species with 
tubers, /. arcticum, Heer, from the ‘‘ Miocene”’ of Spitzbergen.° 
The gigantic Triassic Hyuisetites appear to have produced corre- 
spondingly large tubers, e.g. HL. arenaceum, Jaeg., and £. Dinstert, 
Sternb.!° 
1 Hist. Stirp. indig. Helvet. vol. iii. p. 2 (under No. 1677, not 1676 as 
stated by Duval-Jouve). 
2 Vol. v. p. 245. 
3 Die Chareen und Equiseteen, pl. iv. fig. 6. 
* Mon. Equiset. pl. xxix. Nova Acta Ac. Cs. Leop.-Car. 1865, vol. xxxii. 
5 Heer, Fl. Tert. Helvet. vol. iii. p. 158, pl. exlv. figs. 17-18. 
6 Tbid. vol. i. p. 109, pl. xlii. figs. 2-17. 
7 Trait. pal. vég. vol. i. p. 261. 
8 Fl. foss. Arct. vol. iv. p. 99, pl. xxii. figs. 6-7. 
9 Ibid. vol. ii. pl. i. figs 1-15. 
- 10 Schimper, Trait. pal. vég. Atlas, pls. ix.—xi. 
