Flora of Kwangtung and Hongkong/Character of flora
Character of flora.—A visitor landing on the shore of Kwangtung—the only part of the coast of China washed by tropical seas first notices that the maritime phanerogamic flora is distinctly poor, the only element perhaps of the S. China flora which does not seem remarkably rich to the European visitor. On sandy beaches a close turf usually commences from the high water line varied by patches of Spinifex and Vitex or relieved by an occasional tuft of Crinum, Belamcanda or other sea-side flower. Above this a shrubby belt of Screw-pine often appears with patches of Caesalpinia. On muddy shores there is frequently a dwarf mangrove formation formed by small Rhizophoraceae and Aegiceras in the shallow water. Where salt marshes occur various Cyperaceae are predominant as in other parts of the world.
Supposing now that the visitor proceeds across the fields towards the nearest village, it is very probable that waste ground plants will next engage his attention, and the usual tropical weeds of such places including many species of Desmodium, Solanaceae, Amaranthaceae, Chenopodiaceae, and adhesive-seeded Compositae will be seen. The arable land consists largely of rice fields, which yield a rich flora of water-loving weeds, small Scrophulariaceae predominating.
The drier vegetable fields become covered, if neglected, with Cruciferous and other annuals, or, in the coastal regions, with introduced weeds such as Ageratum and Oxalis.
The farms and villages are nearly always surrounded by fine old Fung-shui (or ‘good luck’) trees, mostly Banyan (Ficus retusa). There may also be clumps of thorny and other large bamboos. Passing on now to an examination of the mountain vegetation, it will at once be noticed that, except in the most inaccessible regions, or those carefully protected (such as Hongkong), their surface in the granitic regions presents the appearance from a distance of smooth grassy downs, whose gigantic and varied forms, broken here and there by rock masses, close in the horizon. In the limestone districts more rock and less down is seen, but, even there, the less remote mountains are destitute of all woods. The cause of this is the old, and perhaps excusable, custom that the Chinese have of cutting down all the wild trees, shrubs and grass near their villages for fuel, and of setting fire to the turf in the dry season to extirpate the remnants of arborescent vegetation. The gullies or ravines, being saved from the grass fires by their rocky character and less pronounced dryness during the north-east monsoon, contain a dense vegetation, particularly rich in flowering shrubs and ferns. This vegetation, which extends into the open ground, wherever allowed so to spread, has a constant element throughout the province of beautiful and abundant shrubby species such as Rhodomyrtus, Melastoma, Gordonia, Gardenia, Mussaenda, and equally common though less conspicuous Strophanthus, Raphiolepis, Pittosporum, Lespedeza, Eurya, Zanthoxylum, Diospyros, and shrubby Euphorbiaceae, and Urticaceae. In the more rocky and damp ravines are found various epiphytic orchids, Gesneraceae and herbaceous Urticaceae.
Between the gullies, the mountain sides have, as has been said, a general appearance of smooth grass. On closer inspection this is found to consist of numerous different formations of lowly growth. On the highest mountains, where clouds are not infrequent even in the dry season, level plains of fairly close turf (Ischaemum, etc.) are found, containing ground orchids, Balsams and mountain Compositae. On the middle and lower slopes there is usually an irregular covering of coarse grass associated with patches of Melastomaceous and Ericaceous undershrubs. On these grassy slopes Hedyotis species and Acanthaceae abound, and here and there may be seen the great white trumpets of Lilium longiflorum or the blue cups of Platycodon. Large areas of such exposed slopes are again not infrequently occupied by thickets of dwarf bamboos. Above these slopes among the rocks and gullies of the higher peaks, Thalictrum and other genera typical of more temperate conditions show themselves, while down the torrent sides may be gathered various species of Utricularia, Gesneraceae, Drosera, Ammannia, and Eriocaulon.
Turning now to the wood flora, much remains to be discovered as to the constituents of the primeval forests which are said to survive in the interior in several parts of the province (see B. C. Henry's Lingnam and Cap. Cauquil's L'Hinterland de Quang-tchéou in the Rév. de Géogr. lv. 175). Meanwhile our knowledge of the subject depends upon the records of the examination of a few patches of forest preserved by the Chinese around their temples and villages for aesthetic or religious purposes. One such wood on low ground in Hongkong was carefully examined by Lo Quai, an officer of the Botanical and Forestry Department, and the constitution of this wood may be taken as an isolated example of such formations. On an acre were found 31 trees of Aquilaria grandiflora, 24 Sterculia lanceolata, 18 Aporvsa leptostachya, the same number of Poupartia Fordii, 10 Antidesma Bunius, 8 Nephelium Bischoffia javanica, Cinnamomum Burmanni and Ardisia quinquegona, and single trees of Litsea sebifera, Helicia erratica and Ficus Liliaceae, Piperaceae, and various grasses and ferns, while huge lianes climb over the trees and hang in weird festoons into the semidarkness of the underwood. THese lianes comprise various species of Derris and Dalbergia, besides numerous Apocynaceae and Asclepiadaceae. On the higher ground the wods are formed of Oak, Holly, Pine, Symplocos, Cordia, Ficus and various Araliaceae, Hamamelidaceae and Lauraceae.
Wood borders and hedges in the province frequently contain subarborescent Rubiaceae, Rhamnaceae, Rosaceae, and Saxifragaceae and support the smaller climbers such as various Cucurbitaceae, Convolvulaceae, Vitis, Smilax and Millettia.
The general character of the flora of the province is distinctly tropical, shrubby and arborescent evergreens predominating.
Of the constituents of the flora the most important is that which is common to the greater part of South China; a distinguishable element is shared with E. Fokien, Formosa and Japan; another in common with Yunnan and Cochinchina is chiefly Indian, while a smaller constituent is Malayan and Australian.
It is probable that many of the districts of the province contain a considerable endemic element in their vegetation. The small island of Hongkong, for instance, has quite a large number of species unrepresented in the neighbouring parts of China and about 100 that are actually endemic.[1] The same character has been noticed to a smaller degree in other parts of the province. It is possible that the drastic climatic conditions, so largely modified by peculiar local circumstances, may have given rise to a system of areas, to some extent botanically isolated, and each with an element of peculiar forms adapted to its phenomena. Thus north-east and south-west aspects, even on the same mountain, support markedly different floras, that of the latter being far less luxuriant. It can hardly be doubted that this differentiation is connected with the monsoons which blow from the two quarters indicated for nearly half the year each, with such marked influence on all vegetation. It has not, however, been explained to the satisfaction of those who are familiar with the effect why the monsoons produce it.
It is again unnecessary to dwell on the rigorous selection that must have occurred during past ages among the coastal ranges of those forms which were adapted to survive typhoons. But it is only intended here to indicate some of the ecological problems which await students in this province, at present facts are not available for their full consideration nor would this be the opportunity to discuss them.
- ↑ Tutcher in Journ. Linn. Soc. xxxviii (1904) 58.