Text-book of structural and physiological botany / by Otto W. Thomé ... and Alfred W. Bennett.

  • Thomé, Otto W. (Otto Wilhelm), 1840-1925.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: Text-book of structural and physiological botany / by Otto W. Thomé ... and Alfred W. Bennett. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

    454/506 (page 432)
    Cupulifer^, Ericaceae, Myrtaceas, Melastomacese, Lauracese, Compositse, Umbelliferse [Labiatas, Cruciferze, Primulaceae]^ Cactaceae, arborescent Euphorbiaceae, [Mesembryanthe- maceae], [figs], Malvaceae, Mimoseae, and Nymphaeaceae. CHAPTER VIII. BOTANICAL GEOGRAPHY. Botanical Geography treats of the distribution of plants on the surface of the earth ; it collects the plants of any par- ticular country into a Flora, and investigates the causes, operating either at the present time or in the past, which have led to each species acquiring its special habitat, and have resulted in only a few plants—termed cosmopolitan — becoming distributed over the whole globe, or even over a large part of it.' The earth does not evei7where produce those plants which are especially adapted to each particular region. If this had been the case, the same species would be constantly met with in widely separated countries that enjoy a similar climate, and no immigration of foreign plants would take place, such as often happens before our eyes. Each species has, in fact, become disseminated only at particular spots ; it has its centre of distribution at the spot from whence it originally sprang ; but the limits of these centres are often obscure, because plants have found conditions suitable for their existence outside these bounds, and feebly represented by our grape-vine, ivy, hop, honeysuckle, [Convol- vulus], &c. ' The phyto-geographical map at the end of the volume must be consulted in connection with this chapter. It indicates the boundaries of the twenty-four phyto-geographical regions adopted by Grisebach in his ' Vegetation der Erde,' each region being coloured uniformly. The regions of a more generally wooded character are coloured green and dark blue, the steppes and deserts yellow and red, while those regions which have no special character of their own are of some other colour. [The statements of Grisebach—on whose work the whole of this chapter is founded—are somewhat too unqualified, both with regard to the boun- daries between the regions and to the characters which distinguish them from one another. — Ed. ]