Fig. 87. Calamocladus equisetiformis (Schloth.).
From a specimen in the British Museum (McMurtrie Collection, no. V. 2963). ca. ⅓ nat. size.
Calamocladus equisetiformis (Schloth.). Fig. 87.
| 1809. | Phytolithus, Martin[648]. |
| 1820. | Casuarinites equisetiformis, Schlotheim[649]. |
| 1825. | Bornia equisetiformis, Sternberg[650]. |
| 1828. | Asterophyllites equisetiformis, Brongniart[651]. |
| 1836. | Hippurites longifolia, Lindley and Hutton[652]. |
| 1855. | Calamites equisetiformis, Ettingshausen[653]. |
| 1869. | Calamocladus equisetiformis, Schimper[654]. |
| 1869. | Annularia calamitoides, Schimper[654]. |
The above synonyms do not exhaust the list[655], but they suffice to illustrate the necessity of a careful comparison in drawing up tables of species, in connection with geographical distribution or for other purposes.
Calamocladus equisetiformis may be briefly defined as follows:—A central axis possessing a hollow pith of Calamitean character, divided externally into well-marked slightly constricted nodes and internodes; from the nodes long narrow and free leaves are borne in whorls; from the axils of some of the leaves lateral branches are given off inclined at a fairly wide angle to the main axis, and bearing crowded verticils of spreading acicular leaves.
The unusually good specimen, 38·5 cm. long, shown on a much reduced scale in fig. 87, illustrates the characteristic habit of this form of Calamocladus. It is from the Radstock coal-field of Somersetshire, one of the best English localities for Coal-Measure plants. An exceedingly good collection of Radstock plants has recently been presented to the British Museum by Mr J. McMurtrie; it includes many fine specimens of Calamites. A small example—probably of this species—from Coalbrook Dale, near Dudley, in Shropshire, and now in the British Museum, illustrates very well the appearance of a young and partially expanded Calamitean foliage-shoot. The central axis, 6·5 cm. in length, includes about 15 internodes, and terminates in a bud covered by several small leaves. Lateral branches are given off at a wide angle, and small unexpanded buds occur in the axils of several of the leaves.
As an example of the leaf-bearing branches which Grand’Eury has recently described as Calamocladus, using the genus in a more restricted sense than is adopted in the present chapter, reference may be made to the fragment shown in fig. 68, A. The foliage-shoots of this type bore verticils of linear leaves, coherent basally in the form of a cup, at the ends of branches and not in a succession of whorls on each branch. The association of reproductive organs, in the form of long and narrow strobili, with Calamocladus is referred to in the sequel.
The specimens described by Grand’Eury are in the École des Mines Museum, Paris; some of the shoots which are well preserved bear a resemblance in habit of growth to the genus Archaeocalamites.
β. Annularia.