. Fossil plants : for students of botany and geology . Paleobotany. 66 CZEKANOWSKIA [ unknown in the genus ( B. paucipartita). Some specimens which may be identical with this type were obtained several years ago by Dr Nathorst from Yorkshire but never fully described: an examination of his unpublished drawings and of specimens col- lected by Mr Hamshaw Thomas convinced me that some forms of Czekanowskia are more freely branched and exhibit more varia- tion in the breadth of the lamina than I had formerly supposed. In specimens of the type first noticed by Nathorst some of the segments
. Fossil plants : for students of botany and geology . Paleobotany. 66 CZEKANOWSKIA [ unknown in the genus ( B. paucipartita). Some specimens which may be identical with this type were obtained several years ago by Dr Nathorst from Yorkshire but never fully described: an examination of his unpublished drawings and of specimens col- lected by Mr Hamshaw Thomas convinced me that some forms of Czekanowskia are more freely branched and exhibit more varia- tion in the breadth of the lamina than I had formerly supposed. In specimens of the type first noticed by Nathorst some of the segments are comparativelybroad and fern-like, a feature that is not seen in the leaves shown in fig. 661. This species affords a striking contrast to Czekanowskia Murrayana in which the long ^^^'^^^^J; ,^'t^T^f: microphylla ^ ^ (Phillips). (British Museum No. 30, leaves are unbranched, and as 283; nat. size.) Nathorst^ suggests the name Snlenites might be revived for the unbranched type; but in the absence of any difference in the epidermal characters, it would seem undesirable to raise to generic rank a feature depending on the simple or branched habit of the leaves of otherwise similar leaf-fascicles. Czekanoivskia rigida Heer. This species, founded on specimens â from Siberian Jurassic rocks^, is characterised by its branched filiform leaves borne on short shoots enclosed by scale-leaves, triangular or lanceolate in form and in some specimens pendulous on slender stalks. Nathorst^ states that the epidermal structure of the scale-leaves is similar to that of the scale-leaves on short shoots of Ginkgo. The characters of the stomata are mentioned in the account of the 1 Nathorst (06) p. 11. 2 Heer (77) ii. p. 70; (78) 11 p. 7; (82) A. p. 19. 3 Nathorst (00).. 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,
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishercambr, bookyear1898
