NATURAL HISTORY
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of species involved is certainly very high. The discharge of the largest freshwater system in South China to the west, and the prevailing Taiwan Current from the north-east, have created a situation where the westerly sector of Hong Kong has a predominantly brackish water fauna, while the eastern sector has a genuine marine fauna. A notable marine animal which has been successfully introduced in the Deep Bay area is the Japanese oyster, Crassostrea gigas. It is now being cultivated.
The freshwater fauna of Hong Kong is relatively poor in variety when compared with that of the mainland of China. This situation is in all probability the result of the absence of a perpetual system of rivers and lakes. Although there are large bodies of water stored in man-made reservoirs, only a few varieties of fish life have been introduced-primarily for water quality control purposes. The indigenous fauna comprises only limited species of cyprinid, loach and goby, while the African Tilapia has also established itself in local waters but its initial introduction cannot be traced. Despite its limited size, Hong Kong has now some 2,700 acres of commercial fish ponds, where the Grey Mullet and seven species of Chinese carps are being produced at a rate of 1.2 tons per acre.
Flora
The flora of Hong Kong is tropical, although at about the northern limit of tropical flora. After centuries of cutting and burning, most of the original arborescent vegetation on the mountainsides has been replaced by herbaceous cover, but in the ravines and on sheltered northern slopes a flora rich in flowering shrubs, low trees and ferns persists. Few high trees are to be found except in the fine fung shui groves preserved around many villages in the New Territories. A great variety of plants in Hong Kong bear flowers of exceptional beauty or fragrance.
The Bauhinia Blakeana, which grows on a medium-sized evergreen tree known as the Hong Kong orchid tree, is among the finest of the Bauhinia genus anywhere in the world and has been adopted as Hong Kong's floral emblem. Named after a former Governor, Sir Henry Blake, it was discovered in 1908 by the Fathers of the French Foreign Missions at Pok Fu Lam. Its origin is unknown and it is a sterile hybrid never producing seed. Another related species is Bauhinia glauca, climbing by means of tendrils, with bunches of pink flowers of sufficient beauty to merit cultivation as a covering for trellises and porches.
There are several species of camellia growing wild on the island and the mainland. All but one have white flowers; the one with red flowers is known only on Hong Kong Island and grows in the Peak district. It is Camellia Hongkongensis, a small tree up to 40 feet in height which comes into flower in November and continues until the middle of March. A new and distinct camellia was discovered in 1955 and named Camellia Granthamiana in honour of the then Governor, Sir Alexander Grantham.
Many local shrubs and a few herbs have very beautiful fruits in striking colours. The Ardisia, the Chloranthus and several wild hollies have brilliant red berries. Numerous yellow fruits with elusive names, one of which is the Maesa, abound the hillsides. There are many inconspicuous green fruits and berries, one of which is the