Text-book of structural and physiological botany . lofty trees or shrubs with multipinnateleaves several feet in length, forming magnificent groups ofplants, in the shade of which other smaller species grewas underwood (Figs. 540-542). Among the largest formsof which these forests were composed were certain Lyco-podiaceae—to which nothing now existing is comparable—known as Sigillaiice and Lepidodendra (Figs. 535-539). gens, 43 genera, 142 species ; Gymnosperms, 56 genera, 363 species ;Cryptogams, 152 genera, 1,172 species; Doubtful, 35 genera, 197species. Since that time the number of both ge
Text-book of structural and physiological botany . lofty trees or shrubs with multipinnateleaves several feet in length, forming magnificent groups ofplants, in the shade of which other smaller species grewas underwood (Figs. 540-542). Among the largest formsof which these forests were composed were certain Lyco-podiaceae—to which nothing now existing is comparable—known as Sigillaiice and Lepidodendra (Figs. 535-539). gens, 43 genera, 142 species ; Gymnosperms, 56 genera, 363 species ;Cryptogams, 152 genera, 1,172 species; Doubtful, 35 genera, 197species. Since that time the number of both genera and species has beenenormously increased, especially by the additions to the Tertiary floramade by Heer and Ettingshausen.—Ed.] [Geologists now distinguish the oldest stratified beds from thesuperimposed Silurian as the Laurentian and Cambrian systems. Theycontain but few remains of organic life.—Ed,] Palceophytology, 421 The former had a columnar unbranched stem, 20 metres inheight, and rising from a square base i metre in diameter,. Fig. 537. —I. Fertile branch; II,terminal branch of Lepidoden-dron (reduced). Fig. 535.—Branching stem oi Lehdodendron, from thecoal-beds of Bohemia (reduced). the bark being covered with a number of longitudinal rows ofdiamond-shaped leaf-scars ; [and it is now generally believed 422 Structural and Physiological Botany. that the fossils known as Stig?naria^ and formerly regarded asa distinct plant, are in reality the roots of Sigillaria.] The
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