. Ein Handbuch der cryptogamic Botanik. Kryptogamen. Fossile VASKULÄRE KRYPTOGAMEN 125 wie sporangiferous Spikes von Equisetum, es nur enthaltenen Sporen von einer Art. Die Gruppe der Calamarie^ - einschließlich der Stiele bekannt als Cala - Milben und Calamodendron und die Frucht bekannt als Calamostachys - wurden von einigen Behörden aus dem Equisetacese auf dem Boden ihrer angeblichen heterospory getrennt, aber ohne ausreichende Ermächtigung von die Fakten Ihrer Struktur als tatsächlich beobachtet. Die Reste der Calamites treten in riesigen Mengen im Auto - boniferous Schichten; anscheinend stellten eine der Mos

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. A handbook of cryptogamic botany. Cryptogams. FOSSIL VASCULAR CRYPTOGAMS 125 like sporangiferous spikes of Equisetum, It contained spores of one kind only. The group of Calamarie^—including the stems known as Cala- mites and Calamodendron, and the fruit known as Calamostachys— have been separated by some authorities from the Equisetacese on the ground of their alleged heterospory, but without sufficient warrant from the facts of their structure as actually observed. The remains of Calamites occur in immense quantities in the Car- boniferous strata ; apparently they constituted one of the most im- portant features of the vegetation of that period, disappearing after the Permian. The stems were fre- quently of gigantic dimensions com- pared with our existing Equisetums, attaining a height of thirty feet and a diameter of four inches or more. They consist of a hollow central cavity, with a cylinder of tracheides in wedge-shaped bundles, separated at their origin by parenchyme, and alternating at the nodes, where there is a diaphragm or ' phragma.' The leaves, which spring in whorls from each node, do not, as in Equi- setites, coalesce laterally into sheaths surrounding the stem. They are narrow and acicular, with a single prominent midrib. At the nodes are occasionally seen saucer-shaped depressions, the scars of the lateral branches, which are sometimes found attached to the primary axis. The growth of the stem is characterised by a considerable secondary increase in thickness; and, since this phenomenon was formerly un- known among living Vascular Cryptogams, it has induced some authori- ties to transfer those examples where it occurs, under the name of Calamodendreae, to Gymnosperms ; but this has been rendered un- necessary from the fact that a secondary growth in thickness occurs also in Lepidodendron and Sigillaria, as well as in Isoetes; and is further contradicted by the fact that fructification of an evidently cryptoganiic character has been found in org

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