. Fossil plants : for students of botany and geology . Paleobotany. XLIV] MESEMBRIOXYLON 209 Mesembrioxylon Schwendae (Kubart). This species is recorded from Attersee in Upper Austria and though probably of Tertiary age it may be derived from Cretaceous strata^. Xylem-parenchyma is present; the bordered pits on the radial walls of the tracheids are in 1—2 rows, usually separate but if contiguous not flattened; if in 2 rows opposite or sub-opposite; the medullary rays reach a depth of 13 cells; there are generally 1—3 pits (fig. 722, A, B) but occasionally as many as 5 in the field; X-E. © B fo
. Fossil plants : for students of botany and geology . Paleobotany. XLIV] MESEMBRIOXYLON 209 Mesembrioxylon Schwendae (Kubart). This species is recorded from Attersee in Upper Austria and though probably of Tertiary age it may be derived from Cretaceous strata^. Xylem-parenchyma is present; the bordered pits on the radial walls of the tracheids are in 1—2 rows, usually separate but if contiguous not flattened; if in 2 rows opposite or sub-opposite; the medullary rays reach a depth of 13 cells; there are generally 1—3 pits (fig. 722, A, B) but occasionally as many as 5 in the field; X-E. © B foo o OQ OQ DO o oo q/oj ool Fig. 722. A, B, Mesembrioxylon Schwendae. C, Mesembrioxylon i Kubart; C, after Gothan.) p. (A, B, after they are bordered and the pore is obliquely vertical, though this feature is inconstant and in some places the pore is circular or the bordered pit may be replaced by a large simple pit. Sclerous cells occur in the pith. Mesembrioxylon aparenchymatosum (Gothan). In this Tertiary species, included by Gothan in Podocar poxy Ion, from Seymour Island ^ there is no xylem-parenchyma; the medul- lary-ray cells have 1—2 elliptical-circular pits in the field and the major axis is oblique. The evidence as to affinity is far from con- clusive. 1 Kubart (ll^) PI. ni. text-figs. 1—10. 2 Gothan (08) p. 8, PL i. figs. 9—11. S. IV 14. 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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