2. Palaeostachya[733].
In this genus the general habit agrees with that of Calamostachys, and in imperfectly preserved specimens it may be impossible to discriminate between Calamostachys and Palaeostachya. The latter form is characterised by the attachment of the sporangiophores in the axil of the sterile bracts, or immediately above them, as shown in figs. 97 and 98.
Examples. Palaeostachya vera sp. nov., P. pedunculata Will. afford examples of this form of strobilus. The genus Palaeostachya includes several species previously described under the genus Volkmannia[734].
Strobili of this generic type are known in organic association with Annularian branches, as well as with Calamocladus and Calamites.
3. Macrostachya.
This generic name was originally applied by Schimper[735] to certain forms of Calamitean stems, of the type afterwards referred to the sub-genus Calamitina by Weiss, bearing long and thick cones. The name is, however, more appropriately restricted to strobili, which differ from the two preceding genera in their greater length (14–16 cm.) and in the more crowded and imbricating whorls of bracts. The internodes of the cones are very short, and each whorl of bracts consists of about 20 coherent members separated at the periphery of the disc into short pointed teeth. The internal structure of Macrostachya has not been satisfactorily determined. An account by Renault[736] of a petrified specimen does not present a very clear idea as to the structural features of this form of Calamitean strobilus.
| Strobilus | Foliage-shoot | Stem |
|---|---|---|
| Calamostachys (Stachannularia) ramosa Weiss[737] | Annularia ramosa Weiss | Calamites ramosus Artis |
| C. (Stachannularia) calathifera Weiss[738] | A. sphenophylloides Zenk. | Stem bearing verticils of long and narrow leaves[739]. Probably a young Calamites |
| C. (Stachannularia) tuberculata (Stern.) | A. stellata(Schloth.)[740] (A. longifolia Brongn.) | Calamites sp.[741] |
| C. Solmsi[742] Weiss | Calamocladus sp. | Calamites (Calamitina) sp. |
| C. longifolia (Stern.)[743] | Calamocladus sp. | |
| Palaeostachya pedunculata Will.[744] | Calamocladus | |
| P. arborescens (Stern.)[745] | Calamites (Stylocalamites) arborescens (Stern.) | |
| Macrostachya[746] | Calamocladus equisetiformis (Schloth.) | Calamites (Calamitina) sp. |
HUTTONIA.
The generic name Huttonia, suggested by Sternberg[747] in 1837, is applied to cones which closely resemble Macrostachya in habit, but differ—so far as our scanty knowledge enables us to judge—in the arrangement of the members. The student must refer to Weiss[748], Solms-Laubach[749] and other writers[750] for a further account of these types, and of another rare and little-known form of cone, called by Weiss Cingularia[751].
Macrostachyan cones have been found attached to stems of Calamites which are included in the sub-genus Calamitina (p. 367). The larger size of Macrostachya as a distinguishing feature is not always a safe test; some cones which belong to Palaeostachya [e.g. P. arborescens Sternb.] and Calamostachys (e.g. C. Solmsi) are much thicker and larger than the majority of species of these two genera.