Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings . orms; yet it would seem that intheir own day and generation they were the leadingFern group. The external characteristics of the groupcan hardly be decided, but the anatomy of their stemsreveals a feature peculiar to all the species. The stemsand leaf-stalks (petioles) were monostelic, which meansthat they were traversed by a single central vascularconducting cylinder. In this respect they differed fromthe majority of modern Ferns (see Plate XXXIL). It was in the Carboniferous and the lat
Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings . orms; yet it would seem that intheir own day and generation they were the leadingFern group. The external characteristics of the groupcan hardly be decided, but the anatomy of their stemsreveals a feature peculiar to all the species. The stemsand leaf-stalks (petioles) were monostelic, which meansthat they were traversed by a single central vascularconducting cylinder. In this respect they differed fromthe majority of modern Ferns (see Plate XXXIL). It was in the Carboniferous and the later PermianPeriods that the Botryopterideee flourished, and con-temporaneous with them were the members of a secondgroup, the Marattiacese (see p. 155); but whereas theformer were exclusively Palaeozoic and probably priorin appearance, the latter have representatives stillexisting. But the few living species are not the sameas those which throve in Palaeozoic times, and the fossilevidence goes to show that the group as a whole wasnext in importance to the Botryopterideae in Palaeozoic Plate XXX. ^^i-m-. HEMP AGRIMONY (Eupatonum cannabmum),Order COMPOSIT/E. 1. Single floret, enlargedt2. HeatI of five florets 3. Bud4:. Seed THE PTERIDOSPERMS 229 times, but that in subsequent ages it gradually dwindleduntil now it has tailed off into the few modern tropicalspecies. Ferns seem to be as important in the worlds vegeta-tion to-day as they have ever been in the past. As agroup they have persisted from the Palaeozoic throughthe Mesozoic Eras to the present time, maintaining afairly even importance, extinct forms, if not giving riseto, at least being replaced by, new Orders. Efforts havebeen made, with some show of success, to trace themodern Osmundacese, represented by the well-knownRoyal Fern {Osmunda regalis) back through Mesozoicrelations to the Botryopterideae.* It is surmised thatthe latter may be a sort of ancient womb from which,after ages of development, a multifarious Fern-proge
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1915
