. Studies in fossil botany . Paleobotany. SPHENOPHYLLEAE IOi cases where it was possible to count them. It has not yet been decided for certain whether the bracts of succes- sive whorls were alternate or superposed ; though the br. Fig. 41.—Sphenophyllwn Dwwsoni. A. Diagram of cone in longitudinal section, showing three whorls, ax, axis ; brt bracts ; sj>, sporangiophores ; sm, sporangia ; br*, whorl of bracts seen from the inside in surface view. (G. T. G.) B. Stele of axis, in trans- verse section. Wood only preserved. J>x, protoxylem-groups, of which there are six in all; p/z, remains
. Studies in fossil botany . Paleobotany. SPHENOPHYLLEAE IOi cases where it was possible to count them. It has not yet been decided for certain whether the bracts of succes- sive whorls were alternate or superposed ; though the br. Fig. 41.—Sphenophyllwn Dwwsoni. A. Diagram of cone in longitudinal section, showing three whorls, ax, axis ; brt bracts ; sj>, sporangiophores ; sm, sporangia ; br*, whorl of bracts seen from the inside in surface view. (G. T. G.) B. Stele of axis, in trans- verse section. Wood only preserved. J>x, protoxylem-groups, of which there are six in all; p/z, remains of phloem. X about 20. Will. Coll. 1049. C. Spores, in superficial aspect. X about 100. B and C after Williamson, Phil. Trans. analogy of the vegetative leaves would lead one to expect superposition, the direct evidence is in favour of an alternate arrangement. The sporangia were. 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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