. Heredity and evolution in plants. Heredity; Plants. THE EVOLUTION OF PLANTS 227 dicotyledons, by a fusion of the two cotyledons into one. ^ On this basis the single seed-leaf of monocotyledons is interpreted as homologous to the two seed-leaves of di- cotyledons. The evidence supporting this suggestion is derived largely from a study of the anatomy of monocoty- ledonous seedlings. "The young epicotyl of monocotyle- donous seedlings contains a single ring of collateral bundles which may even show traces of cambium, much resembling. Fig. 107.—A-B, embryos of a "dicotyledonous monocot
. Heredity and evolution in plants. Heredity; Plants. THE EVOLUTION OF PLANTS 227 dicotyledons, by a fusion of the two cotyledons into one. ^ On this basis the single seed-leaf of monocotyledons is interpreted as homologous to the two seed-leaves of di- cotyledons. The evidence supporting this suggestion is derived largely from a study of the anatomy of monocoty- ledonous seedlings. "The young epicotyl of monocotyle- donous seedlings contains a single ring of collateral bundles which may even show traces of cambium, much resembling. Fig. 107.—A-B, embryos of a "dicotyledonous monocotyledon," A, longitudinal section through an embryo of Tamus communis; B, Tamus communis, entire (.A and B enlarged after Solms-Laubach.). C-G, embryos of "monocotyledonus dicotyledons;" C, D, Dioscorea bonariensis, enlarged (after Beccari); E, Trapa natans, the water chestnut X H (after Barnfioud); F, Pingiiicula vulgaris; G, Pinguicula caudata. {P and G after Dickson, both greatly enlarged.) ; Professor Jeffrey has also called attention to evidence that the anatomy of the stem of the hypotheti- cal ancestor of the Angiosperms was exogenous (dicotyle- donous). Miss Sargant has further pointed out that the few dicotyledons which possess but one seed-leaf (pseudo- monocots) are widely distributed through the dicotyle- donous famiUes, from Ranunculaceae to Umbilliferae, ^Annals of Botany 17: 1-88. Jan., 1903; Botanical Gazette 37: 325- 345. May, 1904, and other 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 Gager, C. Stuart (Charles Stuart), 1872-1943. Philadelphia, P. Blakiston's Son & Co.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectplants, bookyear1920
