Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III. COLONISATION BY OTHER METHODS Very often, plants are enabled to occupy new ground through some special method of growth, or by means of some specialised part (not fruit or seed) which has been developed for the purpose. Sometimes the whole plant is carried to a new place, to which it is either blown by the wind, or floated upon the water. Among plants so transported may be mentioned Manna (Lecanora desertoruui), and other lichens of the Syrian desert, which, in dry weather, are blown over considerable areas, and sometimes heaped up in great quantities. Of other plants, perhaps the best known is the so-called Rose of Jericho (Anastatica Hierochuntica). When dry, the whole plant curls into a sort of spherical ball; then it is said to be torn out and carried away by the wind, but if it should reach a moist place, or be placed in water, the withered-looking branches uncoil, and the plant takes root and produces flowers and fruit. There are quite a number of water plants which, throughout their lives, remain unattached, floating freely, and carried about in the water. The small Lemna, for instance, which has tiny green fronds flattened out in a leaf-like manner, floats on the water and obtains all necessary salts by means of longabsorbing roots. The Bladderwort (Utricularia), the Frogbit (Hydrocharis morsus-ranae), Salvinia, Azolla, and the Florida Hyacinth are all similarly independent, and are never attached to the ground. They arc easily carried about by the current; and sometimes show an extraordinarily quick rate of multiplication. For example the Florida Hyacinth (Eichhornia crassipes), a native of tropical South America, was introduced into the St. John’s river about 1890. In 1897 it had increased to such an extent that large steamers were rendered helpl…
