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NATURAL HISTORY

More than 20 species of shark have been recorded in Hong Kong waters, mainly in the eastern and southeastern areas. Sharks have been sighted in Mirs Bay in the New Territories and as far south as Stanley and Deep Water Bay on Hong Kong Island. Their presence in Hong Kong is a result of the influence of warm ocean currents off the South China Sea during the summer months, in particular, July to September. Sharks which are common in Hong Kong and potentially dangerous are the Hammerhead Shark and species of the True Shark family, which can grow to more than three metres. Other commonly- found sharks, which do not normally attack humans, include the Cat Shark and the Leopard Shark.

Flora

The Hong Kong Herbarium, which contains about 34 000 plant specimens, is more than 100 years old. This government institution, administered by the Agriculture and Fisheries Department, is responsible for collecting, classifying and maintaining authoritative preserved plant specimens representative of Hong Kong flora. It also disseminates knowledge and information by maintaining an index of scientific, Chinese and English common names for the plants of Hong Kong. The herbarium, housed in the New World Centre Office Building in Tsim Sha Tsui, is open to the public.

Situated near the northern limit of the distribution of tropical Asian flora, the plants of Hong Kong are large in number and variety. It is estimated there are about 2 600 species of vascular plants, both native and introduced, and these are listed in the Check List of Hong Kong Plants (Agriculture and Fisheries Department).

Before the introduction of conservation measures, the hillsides were becoming increas- ingly bare of trees as a result of cutting, burning and exposure to the elements. On most, the only cover was coarse grass or scrub. Now many slopes, particularly those in the water catchment areas, have been planted with trees of both local and exotic species. These woodlands, and other areas of countryside, are protected and are being developed for the growing numbers of people who spend increasing amounts of their leisure time in the countryside.

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Remnants of the original forest cover - either scrub forest or well-developed woodlands - are still to be found in steep ravines. These have survived the destructive influences of man and fire through their precipitous topography and moist winter microclimate. It is in such places that many of the more interesting plants grow. Small areas of well-grown woodlands can also be found near the older villages and temples. These fung shui, or sacred groves owe their existence to the protection afforded by generations of villagers in accordance with ancient tradition.

On muddy sea shores, an interesting type of vegetation known as the Dwarf Mangrove Association is occasionally found; there are also patches of vegetation peculiar to sandy beaches. These two vegetation types are particularly well adapted to their environment - providing a useful educational example.

Many species of plants in Hong Kong are noteworthy for the beauty or fragrance of their blossoms. They attract butterflies and insects, while other plants bear fruit and seeds that serve as important sources of food for birds and animals. The orchid species. are described and illustrated in Hong Kong Orchids by G. Barretto and J. L. Young Saye (Urban Council series).

Many villagers have a good working knowledge of the usefulness of some local plants. Aquilaria sinensis is used in the manufacture of scented joss sticks. And among those used in