Oecology of plants : an introduction to the study of plant-communities / by Eug. Warming, assisted by Martin Vahl. Prepared for publication in English by Percy Groom and Isaac Bayley Balfour.

  • Warming, Eugenius, 1841-1924.
Date:
1909
Catalogue details

Licence: Public Domain Mark

Credit: Oecology of plants : an introduction to the study of plant-communities / by Eug. Warming, assisted by Martin Vahl. Prepared for publication in English by Percy Groom and Isaac Bayley Balfour. Source: Wellcome Collection.

    23/444 (page 7)
    We adopt the following sub-division: I. MONOCARPIC HERBS, which include the following groups :— (а) Aestival annual plants. The whole cycle of life is completed within one vegetative period, varying from a few weeks, as in ephemeral desert-plants, to several months. Shoots foliaged with elongated inter¬ nodes (monocyclic). No vegetative organs of storage. The unfavourable season passed in the form of seed.1 Adaptation to dry climates and localities, and to disturbed soil (littoral sand, cultivated soil, and the like). (б) Hibernal annual plants. These germinate in autumn, and con¬ clude their existence with the production of fruit in spring. Rosette- shoots are usually prevalent. Otherwise like those belonging to the preceding group (a). (c) Biennial-perennial (dicyclic, pleiocyclic2) herbs produce in their first vegetative period or in several successive ones rosettes of leaves, and in the following period the flowering shoot, which usually bears foliage. The foliage-leaves of ten live through winter. Buds open. Form of the shoot as in (b). Reserve-food often stored in tuberous axial organs (Beta vulgaris, Daucus Carota). Occurring in cold-temperate climates on open soil, also as cultivated plants. II. POLYCARPIC PLANTS In the case of the polycarpic plants it is necessary to consider, first, their adaptation to climate, and in particular the season unfavourable to plant-life ; secondly, the vegetative season; and, finally, the conditions prevailing in regard to the soil, which Schimper terms edaphic conditions. Of greatest importance is— 1. Duration of the vegetative shoot: lignified axes of trees, shrubs, and undershrubs; perennial herbaceous shoots; herbaceous shoots deciduous after a short period. And closely associated with this is— 2. Length and direction of the internodes : whether the shoots have short internodes (rosette-shoots) or long internodes, and whether the latter are erect (orthotropous) or prostrate and creeping (plagiotropous). 3. Position of the renewal-buds during the unfavourable season [high up in the air, near the soil, under the surface of the soil, or buried in the soil (geophilous)].3 Of less importance is— 4. Structure of the renewal-buds or of buds in general. All stem-apices and very young leaves are protected by leaves ; this protection is accom¬ plished in some cases merely by older foliage-leaves (open buds), in other cases by specially differentiated protective organs, which are either parts of foliage-leaves or definite bud-scales. This depends less upon climate than upon the form of the assimilatory shoots ; short-jointed shoots with leaves in rosettes usually have open buds ; long-jointed shoots are more varied. These differences in the shoot are physiognomi- cally important, not only in themselves, but because the former shoots are branched little or not at all, while the latter are usually richly so. 1 See Ascherson, 1866. 2 Warming, 1884. 3 See the nomenclature in the paper by Raunkiar, 1905, 1907.