. Report on the fossil plants of the lower carboniferous and millstone grit formations of Canada [microform]. Paleobotany; Geology; Paléobotanique; Géologie. 42 CANADIAN FOSSILS. I'l' it' '' I. t- ' . i nil- ' 1 *.:';â '"' â =3 large round scars (Conc-scurs) often ^ith radiating impressions of the basal row of scales. Species with long or drooping leaf-bases have been included in Lepidophloios and Loviatophloios. Species with short leaf bases and cone-scars in two rows have been called Ulodendron and some of them have been included in Sigillaria (sub-genus Clathraria). Decorticated stem
. Report on the fossil plants of the lower carboniferous and millstone grit formations of Canada [microform]. Paleobotany; Geology; Paléobotanique; Géologie. 42 CANADIAN FOSSILS. I'l' it' '' I. t- ' . i nil- ' 1 *.:';â '"' â =3 large round scars (Conc-scurs) often ^ith radiating impressions of the basal row of scales. Species with long or drooping leaf-bases have been included in Lepidophloios and Loviatophloios. Species with short leaf bases and cone-scars in two rows have been called Ulodendron and some of them have been included in Sigillaria (sub-genus Clathraria). Decorticated stems are Bothrodcndron and Ilalonia. Some of the species approach near to the last genus, especially to the Lepidodendra with rhombic leaf-bases like L, tetra'jonmn. Ci/clostiffma.âLeaf-bases undeveloped. Leaf-scars circular or horse-shoe shaped, small, with a central vascular scar. In old trunks of Cyclostigma the leaf-scars become widely separated, and sometimes appear in vertical rows. Young branches of Lepidodendron sometimes have the leaf-scars similar to those of Cyclostigma. Lcptophleum.âLeaf-bases flat, rhombic; leaf-scars obsolete; vas- cular scar single, central. The two last genera are character- istically Devonian. In contradistinction from the trees above mention id, the following general statements may be made respecting other groups. In Conifers the leaf-bases are usually elongated vertically, often scaly in appearance, and with the leaf-scar terminal and round, oval or rhombic, and with a single well-marked vascular scar. In Calamites, Calamodendron and Asterophyllites the scars of the branchlets or leaves are circular or oval with only a single vascular scar, and situated in verticils at the top of well-marked nodes of the stem. In Tree-ferns the leaf-bases are large and usually without a distinct articulating surface. The vascular bundles are numerous. Protopteris has rounded leaf-scars with a large horse-shoe shaped bundle of vessels above and small bund
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