. Studies in fossil botany . Paleobotany. 528 STUDIES IN FOSSIL BOTANY of growth, but, generally speaking, annual rings cannot be distinguished. The medullary rays are narrow ; the principal rays, P p* ep sc k. Fig, 190.—Coi-daites (Araucarioxyloii) Brandlingii. A, section (somewhat restored) of middle part of stem, showing discoid pith (/) and wood (_r). x about 7. R, Inner part of wood, with adjacent cells of pith, in radial section. /, pith-cells ; px, narrow spiral tracheides of protoxylem'; sp, wider spiral tracheides ; sc, scalari- form tracheides ; bt, tracheides with bordered p
. Studies in fossil botany . Paleobotany. 528 STUDIES IN FOSSIL BOTANY of growth, but, generally speaking, annual rings cannot be distinguished. The medullary rays are narrow ; the principal rays, P p* ep sc k. Fig, 190.—Coi-daites (Araucarioxyloii) Brandlingii. A, section (somewhat restored) of middle part of stem, showing discoid pith (/) and wood (_r). x about 7. R, Inner part of wood, with adjacent cells of pith, in radial section. /, pith-cells ; px, narrow spiral tracheides of protoxylem'; sp, wider spiral tracheides ; sc, scalari- form tracheides ; bt, tracheides with bordered pits, x 95. Kidston Coll. 185 (Coal- measures of Dudley). (G. T. G.) between the original bundles, may be as much as three cells in thickness, but the secondary rays are usually one, or at most two cells thick. The narrow rays have. 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 Scott, Dukinfield Henry, 1854-1934. London, A. and C. Black
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