Volume 1

The natural history of plants : their forms, growth, reproduction, and distribution / from the German of the late Anton Kerner von Marilaun by F.W. Oliver ; with the assistance of Lady Busk, and Mrs. M.F. Macdonald ; with about two thousand original woodcut illustrations.

  • Anton Joseph Kerner von Marilaun
Date:
1903
Catalogue details

Licence: In copyright

Credit: The natural history of plants : their forms, growth, reproduction, and distribution / from the German of the late Anton Kerner von Marilaun by F.W. Oliver ; with the assistance of Lady Busk, and Mrs. M.F. Macdonald ; with about two thousand original woodcut illustrations. Source: Wellcome Collection.

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    reserves of food necessary for the founding of a new establishment. It would be of no use, and contrary to the economy of plants, if reserve materials were de- posited in any other parts, say in the stem or roots, since these parts shrivel and dry up as soon as the seeds are dispersed, and the energy expended in the manu- facture and storage of starch, fat, sugar, and other reserve food would be expended in vain. The roots of annual plants are therefore satisfied with delivering the necessary water and the required amount of food-salts to the plant during its short period of vegetation, and with providing a suitable attachment to the substratum; they waste no energy in founding subterranean reservoirs. In biennial and perennial plants it is quite otherwise. Biennial plants—as well-known examples of which may be taken the various roots used as vegetables, the Carrot (Daucus Carota), the Turnip (Brassica Rapa rapacea), and the Beet-root (Beta vulgaris rapacea)—develop during the first year a very short stem with foliage-leaves crowded in a rosette, and a thick, fleshy tap-root (radix palaris), or turnip-shaped root (radix napiformis). When vegetative activity recommences in the second year, an erect shoot with foliage and flowers is constructed at the expense or at any rate with the help of the materials stored up in the thickened root; fruits are produced from the flowers, and after the ripening of the seeds the whole shoot dies off together with the exhausted roots. In perennial plants the roots, when they serve for the reception of abundant reserve-materials, are usually considerably thickened; but in these plants it is the clustered root-fibres springing from the lower end of the underground part of the stem, after the primary root has died off, which undergo this development. When the thickening is symmetrical and fusiform, as in the Orpine (Sedum Telephium) and in the white-flowered Orobus Pannonicus, the roots are called fusiform (radices grumosce)] when they are swollen at intervals into knots, as in the Dropwort (Spiraea Filipendula), and in the yellow Day-lily (Hemerocallis fiava), they are termed nodose (radices nodosce). Many of our terrestrial orchids have two kinds of roots united in a fascicle, long cylindrical vermiform roots and short thick roots filled with reserve-materials which look very like tubers, and are called tuberous roots (radices tuberosce). The Mediterranean flora and that of steppes, where in midsummer the vital activity of plants is much reduced, are particularly rich in plants whose roots are developed as storehouses for reserve materials. Plants of widely different families (e.g. Ranunculus Neapolitanus, Centaurea napuligera, Valeriana tuberosa, Rumex tuberosus, Asphodelus albus) there form thickened fascicled roots crowded with reserve-materials which pass through the dry season unharmed underground, and in the next period of vegetation supply the materials for the rapid construction of epigeal foliage and flowering shoots. These thickened bundles of roots are characteristic of the perennial, parasitic species of the genus Pedicularis. They serve for the storage of reserve foods, for the fixing of the plant, and for the absorp- tion of nourishment, but the latter function is here carried on by means of suckers, which are developed at the end of the thickened fusiform fibres, and which attach themselves to the roots of the host plants in the manner described on p. 179.