Observations on the Structure of Fossil Plants Found in the Carboniferous Strata, Volume 2 |
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Adolphe Brongniart Anabathra appear bark barred tubes Binney Bracts Brongniart Brooksbottom Burnley Calamites Calamodendron commune Carboniferous Carruthers cells central axis Coal-measures column composed Cone described Diploxylon elongated utricles epidermis evidence external characters faisceaux figured fossil plants genus Geol Halonia regularis Hooker inch in diameter inner radiating cylinder internal structure Lancashire leaves Lepidodendron Harcourtii Lepidostrobus Lindley and Hutton longitudinal section Lycopodiacées Macrospores Magnified 5 diameters medulla médullaires medullary rays Memoir nearly nodules orthosenchymatous tissue outer radiating cylinder oval parenchyma parenchymatous tissue pith Plate portion preserved pseudo-vascular radiating series resembling ribs and furrows root rootlets scales or bracts scars Schimper seam of coal seen showing structure Sigillaria elegans Sigillaria vascularis similar species specimens of Sigillaria sporangia Sporangium spores stem of Lepidodendron Stigmaria Stigmaria ficoides Strata tangential section tige trace transverse section traversed upper utricles vascular bundles vascular cylinder vascular tissue wedge-shaped masses woody cylinder zone
Popular passages
Page 72 - The primary ones are of large size, and are arranged in regular quincunctial order; they are composed of thick masses of mural cellular tissue. A tangential section of each ray exhibits a lenticular outline, the long axis of which corresponds with that of the stem. These rays pass directly outwards from pith to bark, and separate the larger woody wedges which constitute so...
Page 106 - Not unfrequently, the flattened side turns in so as to form a groove. The surface is marked in quincuncial order with pustules, or rather depressed areolae, with a rising in the middle, in the centre of which rising a minute speck is often observable. From different modes and degrees of compression, and, probably, from different states of the original vegetable, these areolae assume very different appearances, sometimes running into indistinct rimae, like the bark of an aged willow, sometimes, as...
Page 107 - ... or root growing in a direction nearly horizontal in the soft mud at the bottom of freshwater lakes or seas, without branches, but sending out fibres from all sides; that it was furnished in the centre with a pith of a structure different from the surrounding wood or cellular substance, more dense and distinct at the older end of the plant...
Page 73 - Gyntnosperms, as suggested by M. Brongniart, must be abandoned. The remarkable development of exogenous woody structures in most members of the entire family indicates the necessity of ceasing to apply either to them or to their living representatives the term Acrogenous. Hence the author proposes a division of the vascular cryptogams into an Exogenous group, containing...
Page 67 - Lepidodendron nourished, it is most important to observe whatever is peculiar in those organs by which the plants were connected with the physical conditions around them. Geologists have too much overlooked such considerations in their deductions as to the physical phenomena of a period from the plants and animals that then existed. They have often taken for granted that the known conditions of the living species of a genus are true also of the fossil members of the same genus. In the want of other...
Page 9 - A Calamodendron as usually seen is a striated cast with frequent cross lines or joints; but when the whole stem is preserved, it is seen that this cast represents merely an internal pith-cylinder, surrounded by a woody cylinder composed in part of scalariform or reticulated vessels, and in part of wood-cells with one row of large pores on each side.
Page 72 - ... and the structure is pronounced an early type of an exogenous cylinder. From this cylinder alone the vascular bundles going to the leaves are given off. He describes Stigma/ria ("well-known," he says, " to be a root of Sigillaria,") as having " a cellular pith without any trace of a distinct outer zone of medullary vessels such as is universal amongst the Lepidodendra. The pith is immediately surrounded by a thick and well-developed ligneous cylinder, which contains two distinct sets of primary...
Page 86 - Halonia, consist of the usual parenchymatous tissue, but seems to be composed of large quadrangular cells arranged in perpendicular series, and presenting an appearance as though each minute column was confined within a slight membrane or tube.
Page 42 - Lepidostrolus, but differs in each scale of the cone supporting a double series of roundish sporangia, whereas in that genus each scale supports only one roundish sporangium.
Page 71 - ... the cells of which are developed into a tubular and almost vascular form ; but the vessels are never barred, being essentially of the fibrous type. Externally to this bast-layer is a more superficial epiderm of parenchyma, supporting the bases of leaves, which consist of similar parenchymatous tissue. Tangential sections of these outer cortical tissues show that the so-called