. Fossil plants : for students of botany and geology . Paleobotany. 116 LYCOPODIALES [CH. by their darker colour from the bulk of the parenchymatous tissue d. This section also illustrates another characteristic feature of Lepidodendron, namely the presence of a ligule and a ligular pit: the former is represented by a carbonised patch of tissue and the latter extends from the surface of the cushion at b, just above the leaf-scar, almost to the level of the leaf-trace, It A comparison of this section with figs. 146 and 147 will make clear the relation of the several parts of the cushion and lea
. Fossil plants : for students of botany and geology . Paleobotany. 116 LYCOPODIALES [CH. by their darker colour from the bulk of the parenchymatous tissue d. This section also illustrates another characteristic feature of Lepidodendron, namely the presence of a ligule and a ligular pit: the former is represented by a carbonised patch of tissue and the latter extends from the surface of the cushion at b, just above the leaf-scar, almost to the level of the leaf-trace, It A comparison of this section with figs. 146 and 147 will make clear the relation of the several parts of the cushion and leaf-scar. The gaps gg, seen in fig. 148, A and B, mark the position of. Fig. 150. Lepidodendron vasculare. Leaf-cushions in longitudinal section, (From a specimen in Dr Eidston'a Collection.) the delicate meristematic zone or phellogen which arises close to the bases of the leaf-cushions; the phellogen has already pro- duced a few rows of radially disposed elements, represented by short radial lines in the drawing, which constitute secondary cortical tissue. In older shoots the amount of the secondary cortical tissue developed on the inner side of the phellogen is consider- able (cf figs. 152, 153).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Seward, A. C. (Albert Charles), 1863-1941. Cambridge : University Press
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishercambr, bookyear1898
