. Fossil plants : for students of botany and geology . Paleobotany. XXXVII] WILLIAMSONIA 453 of secretory sacs and a few patches of scalariform tracheids: there is evidence of the occurrence of peripheral conducting tissue in the lower portion of the axis such as occurs in the peduncles of American species of Cycadeoidea described by Wieland. The bracts nearer the axis are more shrivelled than those farther away, the result of the feebler development of hypodermal stereome in the more internal bracts. Sunken stomata occur on the lower surface of some of the bracts: several collateral bundles a
. Fossil plants : for students of botany and geology . Paleobotany. XXXVII] WILLIAMSONIA 453 of secretory sacs and a few patches of scalariform tracheids: there is evidence of the occurrence of peripheral conducting tissue in the lower portion of the axis such as occurs in the peduncles of American species of Cycadeoidea described by Wieland. The bracts nearer the axis are more shrivelled than those farther away, the result of the feebler development of hypodermal stereome in the more internal bracts. Sunken stomata occur on the lower surface of some of the bracts: several collateral bundles are present in each and large secretory ducts are abundant. The. Fia. 564. WilUamsonia scoiica. Transverse section near the distal end of a mioropylar tube and the surrounding polygonal interseminal scales, (ca. x 100.) numerous hairs on the bracts and the sterile region of the cone are outgrowths of epidermal cells; most of them consist of a short basal cell and a very long thick-walled tubular hair reaching a length of several centimetres. In some cases the basal cell bears a group of short cells each of which is the starting-point of a long hair: this is worthy of notice from the point of view of comparison with the ramenta of other Bennettitalean flowers. The short proximal cell of a hair is surrounded by a cuticular ring like a rounded base-moulding where it rests on the epidermis: this has been aptly compared to the dark rings that form. 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
