_Calamopitys Saturni_ Unger. Our knowledge of this and other species is confined to stems and petioles. One of the largest examples of the species is a piece of stem with a diameter of 1·5 cm.: the single stele consists of a parenchymatous pith enclosed by secondary xylem made up of tracheids with 4–8 rows of bordered pits and medullary rays more than one cell broad and of considerable depth. Between the inner edge of the wood and the pith are groups of primary xylem (fig. 454, B, _x_) which, like those in _Lyginopteris_, constitute the leaf-traces: each has a single internal protoxylem strand (fig. 455, B). The comparatively wide cortex consists of parenchyma with a hypoderm of the _Sparganum_ type. Each primary xylem-strand passes out as a single leaf-trace through the secondary xylem and on emerging divides into two as in _Lyginopteris_: these branch in the cortex and the two are replaced by six in the leaf-base (fig. 454, B–D). As seen in figs. 454, C, 455, A, the boundary between the stem proper and the decurrent leaf-base is marked by a line of stereome strands. The petioles of _Calamopitys Saturni_ agree generally in structure with the imperfect specimens on which Unger founded his genus _Kalymma_[491], so named in reference to the structure of the hypodermal zone. A specimen described by Solms-Laubach as a _Kalymma_ petiole occurs in organic connexion with a stem of _Calamopitys_ (fig. 454, C: a detached petiole is shown in fig. 454, D). The identification by White[492] of this attached petiole with Unger’s _K. grandis_ has been confirmed by Scott and Jeffrey. A fuller account of _Kalymma_ (fig. 456) is given on a later page, as the petioles so named belong to more than one species of stem. [Illustration: Fig. 454. _Calamopitys Saturni._ B, stem with leaf-base; _x_, primary xylem and pith; black patches represent leaf-traces; C, stem with two leaf-bases; D, section of petiole. (After Solms-Laubach.)] [Illustration: Fig. 455. _Calamopitys Saturni._ A, stem with leaf-bases; × 5. B, stele showing leaf-trace after emerging from the secondary xylem; × 16. (After Zalessky.)] In _Calamopitys Saturni_ we have a plant agreeing with _Lyginopteris_ in the possession of secondary xylem of the manoxylic type and in the structure of the common primary bundles, while it is distinguished from _Lyginopteris_ by the greater number and by the structure of the bundles in the axis of the leaf. _Calamopitys annularis_ (Unger)[493].