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Show 326 PHYSIOGNOMY OF PLANTS. of vegetation;" and on the other hand, "instances of a sudden change in the vegetation unaccompanied by any diversity of geological or other features." (Joseph Hooker, Botany of the Antarctic Voyage of the Erebus and Terror, 1844, p. 210.) Is there any species of Erica in Central Asia? The plant spoken of by Saunders in Turner's Travels to Thibet (Phil. Trans. vol. lxxix. p. 86), as having been found in the Highlands of Nepaul (together with other European plants, Vaccinium myrtillus and V. oxycoccus), and described by him as Erica vulgaris, is believed by Robert Brown to have been an Andromeda, probably Andromeda fastigiata of W allich. No less striking is the absence of Call una vulgaris, and of all the species of Erica throughout all parts of the Continent of America, while the Calluna is found in the Azores and in Iceland. It has not hitherto been seen in Greenland, but was discovered a few years ago in Newfoundland. The natural family of the Ericacere is also almost entirely wanting in Australia, where it is replaced by Epacridere. Linnreus described only 102 species of the genus Erica; according to Klotzsch's examination, this genus really contains, after a careful exclusion of all mere varieties, 440 true species. ( 20) p. 241.-" The Cactus form." If we take the natural family of the Opuntiacere separated from the Grossulariacere (the species of Ribes), and, viewed as it is by Kunth (Handbuch der Botanik, s. 609), we may well regard it as belonging exclusively to America. I am aware that Roxburgh, in the Flora Indica (inedita), cites two species of Cactus as belonging to South Eastern Asia ;-Cactus indicus and C. chinensis. Both are widely disseminated, and are found in a wild state (whether they were originally wild or have become so )1 and are distinct from Cactus opuntia and C. coccinellifer; but it is remarkable that the Indian plant (Cactus indicus) has no ancient Sanscrit name. Cactus chinensis has been introduced in St. Helena as a cultivated plant. Now that a more general interest has at length been awakened .on the subject of the original distribution of plants, future investigation will dispel the doubts which have been felt in several quarters respecting the existence of true Asiatic Opuntiacere. In the animal kingdom particular forms are found to occur singly. Tapirs were long regarded |
