CHAPTER VI. 
SYSTEMATIC DESCRIPTIONS OF THE FOSSIL PLANTS. 
Phylum EQUISETALES. 
Genus EQUISETITES Sternberg, 1833. 
{Vers. Darstell. Flora Vorwelt, Heft vii, p. 43.) 
Equisetites Nicoli sp. nov. Plate III, fig. 2. 
Diagnosis.- —Stems fairly slender, 1 cm. or more across. Internodes smooth, 
3 cm. or more in length. Leaves, between 15 and 20 in a whorl, united below for 
a short distance into a sheath closely clasping the stem, the upper portions free, 
very slender and acuminate, exceeding 2 cm. in length. Nodal diaphragms, 5-7 mm. 
in diameter. 
Description of the Specimens. —Fragments of two leafless stems, both showing 
displaced nodal diaphragms, are figured, natural size, on Plate III, fig. 2. The more 
complete of these measures about 3-5 cm. in length and about 1 cm. in breadth. The 
nodal diaphragms have a diameter of 5-6 mm. The external surface of the stem 
appears to be smooth, or only faintly and discontinuously grooved. On the back 
of the same specimen other, fragments of similar stems and of leaf-whorls occur, and 
in some cases parts of the leaf-sheath are probably in continuity with the stems. 
Remarks. —The nodal discs of the New Zealand plant very closely resemble those 
of Equisetites broraensis Stopes(l), from the Jurassic of Scotland, an imperfectly known 
type, of which neither the stems nor the leaves have as yet been described. It would 
therefore be unwise for the present to refer the Gore specimen to the British species. 
Equisetites Nicoli also approaches E. lateralis (Phil.), from the Lower Oolite of 
Yorkshire and Italy. They may even be identical, though at present I should be 
inclined to regard them as specifically distinct. There is still much mystery attaching 
to the Yorkshire species. Professor Seward(2) at one time regarded it as distinct 
from Equisetites columnaris, though latterly(3) he has united it with that species. I 
think it is quite certain that the New Zealand plant is not identical with E. columnaris 
(Brongn.). There are, however, several points of agreement with E. lateralis. The 
displaced nodal diaphragms, seen on Plate III, fig. 2, are similar to those of E. lateralis, 
though probably not identical. There are few r er “ spokes in the wheel ” in the New 
Zealand fossil. 
The Rhsetic Equisetites Milnsteri Sternb., though showing some features in common, 
is far removed from the new Zealand fossil. The very fragmentary Australian specimen, 
termed by Tenison-Woods(4) Equisetum rotiferum, I regard as undeterminable speci¬ 
fically, but it shows displaced nodal diaphragms not unlike those of Equisetites Nicoli. 
There has previously been some difference of opinion as to which genus : — Equisetites, 
Phyllotheca, or even Schizoneura —such fossils should be referred to, but in this case 
there can be no doubt that the correct genus is Equisetites. In this genus the leaves 
are united at the base into a sheath, closely oppressed to the stem, as in this fossil. 
In Phyllotheca there is also a basal sheath, but it is a loose, sac-like, spreading structure, 
not clasping the stem. 
(1) Stopes (1907), p. 378, pi. xxvii, fig. 2. 
(2) Seward (1898), vol. i, p. 275, text-figs. 03, 
(3) Seward (1900), vol. i, p. 50, text-figs. 3, 4. 
(4) Tenison-Woods (1883), p. 66, pi. vi, figs. 
