. Fossil plants : for students of botany and geology . Paleobotany. XXIX] LYGINOPTERIDEAE 39 i. Stem. The petrified stem on which Binney founded the species was first figured by Dr Arber^ from a section in the Binney collection in the Sedgwick Museum, Cambridge: this section (13mm. in diameter) is reproduced in fig. 402. The most striking features are: (i) the pith consisting of an unusually large and irregular group of dark thick-walled parenchyma, (ii) the broad cylinder of manoxylic secondary xylem characterised by multiseriate medullary rays, (iii) the outer cortex composed of dark radiall
. Fossil plants : for students of botany and geology . Paleobotany. XXIX] LYGINOPTERIDEAE 39 i. Stem. The petrified stem on which Binney founded the species was first figured by Dr Arber^ from a section in the Binney collection in the Sedgwick Museum, Cambridge: this section (13mm. in diameter) is reproduced in fig. 402. The most striking features are: (i) the pith consisting of an unusually large and irregular group of dark thick-walled parenchyma, (ii) the broad cylinder of manoxylic secondary xylem characterised by multiseriate medullary rays, (iii) the outer cortex composed of dark radially. Fia. 402. Lyginopteria oldhamia. Transverse section of the type-specimen in the Binney Collection, Sedgwick Museum, Cambridge. (After Arber.) disposed and oblique bands of mechanical tissue separated from one another by partially destroyed and tangentially elongated parenchymatous elements. It is this outer cortex that Williamson aptly compared with the Eoman numerals on a clock-face. In the perimeduUary region and in contact with the inner edge of the secondary-xylem cylinder are six strands of primary xylem 1 Arber, E. A. N. (02).. 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
