. Fossil plants : for students of botany and geology . Paleobotany. 242 CONIFEBAIiES [CH. (fig. 730, C) in the field resemble those of some Pines and other Abietineae as also those of Sciado-pitys (fig. 693, N): in Xenoxylon there are no resin-canals and no xylem-parenchyma. Grothan considers that while differing in the sum of its characters from any other type of Conifer, Xenoxylon shows most resemblance to Gothan's genus Phyllocladoxylon (= Mesembrioxylon Sew.)^, a genus including fossil species which suggest affinity not only with Phyl- locladus but with other members of the Taxaceae. In hi
. Fossil plants : for students of botany and geology . Paleobotany. 242 CONIFEBAIiES [CH. (fig. 730, C) in the field resemble those of some Pines and other Abietineae as also those of Sciado-pitys (fig. 693, N): in Xenoxylon there are no resin-canals and no xylem-parenchyma. Grothan considers that while differing in the sum of its characters from any other type of Conifer, Xenoxylon shows most resemblance to Gothan's genus Phyllocladoxylon (= Mesembrioxylon Sew.)^, a genus including fossil species which suggest affinity not only with Phyl- locladus but with other members of the Taxaceae. In his account of Xenoxylon phyllocladoides from King Charles Land Gothan describes instructive examples of the efEect of the action of fungal hyphae on the structure of tissues. The genus may be described as a generalised type exhibiting features shared by the Araucarineae and Taxaceae. XIII. ANOMALOXYLON. Gothan. Anomaloxylon magnoradiatum Gothan. Gothan proposed this name for some Upper Jurassic wood from Spitz- bergen^ which cannot be definitely assigned to a family-position: its most striking feature is the occurrence of large spindle-shaped medullary rays containing a large 'canal,' or spaces lined by a single layer of cells (fig. 731). The rings of growth are well marked, the summer-wood being composed of avery few rows of tracheids in abrupt juxtaposition to the larger spring elements, a character associated with roots. There are no vertical resin-canals and no regular or typical horizontal canals. Xylem-parenchyma is rare or absent. The bordered pits on the radial walls of the tracheids are in 1—2 rows, separate and circular or, more frequently, con- tiguous and more or less flattened but, if in two rows, not alternate. The medullary rays are uniseriate, generally 5—7 cells deep, or in places forming broad and deep spindle-shaped areas either empty or containing a large circular canal- like passage. These peculiar rays, as seen in a tangential section of the wood, are a
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