. Fossil plants : for students of botany and geology . Paleobotany. XXXIl] ERISTOPHYTON 197 Eristophyton. Zalessky. Eristofhyton fasciculare (Scott). The generic name Eristo- phyton^ was proposed by Zalessky^ for two incomplete stems of Lower Carboniferous age provisionally^ referred by Scott to Araucarioxylon and subsequently to Calamopitys*. The species E. fasciculare was founded on material obtained by Dr Kidston from the Lower Carboniferous of Dumbarton, Scotland, and on a specimen in the Williamson collection from Northumberland. There is a small pith of parenchyma, 2—3 mm. in diameter, w
. Fossil plants : for students of botany and geology . Paleobotany. XXXIl] ERISTOPHYTON 197 Eristophyton. Zalessky. Eristofhyton fasciculare (Scott). The generic name Eristo- phyton^ was proposed by Zalessky^ for two incomplete stems of Lower Carboniferous age provisionally^ referred by Scott to Araucarioxylon and subsequently to Calamopitys*. The species E. fasciculare was founded on material obtained by Dr Kidston from the Lower Carboniferous of Dumbarton, Scotland, and on a specimen in the Williamson collection from Northumberland. There is a small pith of parenchyma, 2—3 mm. in diameter, with eight strands of primary xylem of varying diameter (fig. 457). Fig. 457. Eristophyton fasciculare. Transverse section showing the relation of primary (black) to secondary xylem. (After Scott.) and in each a single protoxylem-group. The primary xylem elements are considerably larger than the secondary tracheids. These xylem-bimdles are leaf-traces and their disposition points to a phyllotaxis of f. The traces attain their maximum size when about to pass out through the secondary xylem. The tracheids are reticulate and scalariform while some have an intermediate type of pitting. A leaf-trace on reaching the pith gradually moves further from the xylem-cyhnder and may be separated from it by 2—6 layers of parenchyma: as it passes down the pith the protoxyiem strand assumes an almost endarch position consequent on the reduction of the centripetal xylem. In Scott's words, 'each circummedullary strand branches at regular ^ ipurrSs, to be disputed. 3 Scott (992). 2 Zalessky (11). 1 Scott (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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