Shopping Basket: 0 Total: $0
by Dr. Clifford Parks
AN INTRODUCTION TO CAMELLIA SPECIES
GENERAL COMMENTS: The genus Camellia is endemic to southeastern Asia, and contains a large number of species. In fact, it is the largest genus in the plant family Theaceae. More than 400 species have been named and published, but the number has been reduced by combination during taxonomic revisions. There is much disagreement concerning the status of many camellia species. Three different taxonomic authorities place the number of valid species from 80 to 280. Nevertheless, a large majority of the species is native to China.
Cultivars of Camellia species are important ornamental shrubs, flowering trees and economic plants in the warm temperate and subtropical zones. Starting about 1000 years ago cultivars were developed from wild species by selection and breeding in China and Japan, and many fine garden forms were developed. Visitors from the west collected species and cultivars and introduced them to western gardens during the colonial period. Since that time, camellias have become fashionable ornamentals in the milder zones of the world.
Extracts from the leaves of several different Camellia species are the source of tea. Tea is widely cultivated in southeastern Asia and to a lesser degree in mild regions in other parts of the world. In China and Japan edible oil of high quality is extracted from the seeds of several different Camellia species. In China camellias are cultivated for seed oil production.
As long as Camellia species have been in cultivation, horticulturists have been selecting the most ornamental individuals for garden culture. In recent decades plant breeders have recombined the traits of different species into hybrids, and large numbers of these hybrid cultivars are now in gardens. Plant breeders recognize that there are genetic traits in many of the uncultivated species that could improve our garden cultivars.
Breeding programs are now under way to bring these traits into garden forms.
Despite the wide diversity of Camellia species, only a few species are now widely grown as garden ornamentals. Most cultivars in cultivation as ornamentals are C. japonica, C. reticulata, C. sasanqua, C. saluenensis or hybrids among them.
There have been many different taxonomic treatments of the genus Camellia, but three are most important. In 1958 Sealy monographed the genus and placed the species into morphologically similar groups known as sections. Chang produced a revision in 1981, and with much more material at his disposal he named many new species and modified and added several sections to the genus. In his treatment in 2000 Ming reduced the number of species by combination and reduction, and he more closely follows Sealy’s treatment. There are major differences in the treatment of Camellia species by the three authors.
FAMILY THEACEAE: The genus Camellia belongs to the small plant family, Theaceae or tea family. The family can be divided into three groups of similar genera (Prince and Parks, 2002).
1. Gordonia and Franklinia are native to the New World, and Schima is native to southeastern Asia.
2. Stewartia is native to southeastern North America and southeastern Asia, while Hartia is native only to southeastern Asia.
3. Camellia and related genera, Polyspora, Pyrenaria and Tutcheria are native to southeastern Asia, and Laplacea is native to tropical America.
The small evergreen tree, Gordonia, flowers in the summer on long stems, and the genus Franklinia is deciduous but otherwise similar. Schima is evergreen and also summer flowering. The genera Stewartia and Hartia are deciduous or evergreen and flower in the spring. The genera closely related to Camellia are similar to Camellia and can be confused with it, but these genera are separated by important morphological details. Some species of Polyspora are very large trees with very showy flowers, and are beginning to appear in cultivation. Many species of the various theaceous genera are very ornamental and are widely cultivated,
MORE BACKGROUND ON CAMELLIA: The genus Camellia is native to southeastern Asia, and is an important component of the warm temperate and subtropical forests of that region. Over the entire range of distribution, climates range from cool temperate to tropical, moist to rather dry and at elevations from sea level to 3200m. If undisturbed, most Camellia species become small trees, but some remain shrubs. Most species are subcanopy trees, rarely top canopy, and occur in woodlands that range from rich woods to those that are dry and sparse. Many resilient species regenerate from stumps in deforested areas and survive as shrubs in pastures and meadows. Mature Camellia trees in old forests are known that are more than ½ meter in diameter and 10 to 15 meters in height.
There is much that remains to be discovered about this genus. It occurs over a wide area that is mountainous and rugged, and where little botanical work has been done. Accessions are still being discovered that are new species. As has already been pointed out, there is disagreement over the number of actual species. The recent monographer Chang lists 280 species while Ming lists 119 in his revision. Analyses of population structure and variation will help to resolve much of this problem, but little of that work has been, or is being, done. An important first stem is the development of the comprehensive International Camellia Species Garden at Jinhua where
most of the known Camellia species are being grown under the same environmental conditions.
While westerners think of camellias primarily as garden flowers, tea production is economically more important in Asia. Many species in Section Thea of the genus Camellia are cultivated for tea production, but the cultivars of C. sinensis var. sinensis, C. sinensis var assamica and C. taliensis are most important. Over the world tea is produced in more than 40 countries. In China tea has been used as a beverage for more than 2000 years, and for more than a 1000 in Japan.
High quality edible oil can be extracted from Camellia seeds. The oil is extracted from many different species. In China several species are grown in orchards for seed oil production, and the oil produced is used for cooking in the areas where it is produced. Since the oil has good health properties, its production and use is being explored in the United States.
Evidence from Chinese literature of 1000 or more years ago provides clear evidence that Camellia species were cultivated as ornamentals at that time. A similar culture developed in Japan slightly later. The cultivation of camellias has spread over all of the mild temperate regions of the world. Camellia japonica with its vast array of cultivated forms is most widely grown. Another Japanese species, C. sasanqua, is widely cultivated in such diverse places as Australia and the southeastern United States. Camellia reticulata and its hybrids are widely grown as garden trees and the flowers are often displayed in flower shows. Other species are occasionally cultivated, and a general interest in species cultivation is increasing.
IMPORTANT SPECIES OF THE GENUS CAMELLIA
FOR GARDEN CULTIVATION:
The species of the genus are arranged into sections according to visual and morphological similarity. We will list important species by sections as presented in Collected Species of the Genus Camellia—An Illustrated Outline by Gao, Parks and Du. You are referred to that survey for more detailed information. We will mention those species than are now at least minimally cultivated in private and public gardens. Species that are poorly known and not cultivated outside of China will not be included in this list. Taxonomic problems will be discussed with each species.
Section Archecamellia: Camellia amplexicaulis is a subtropical species that can withstand little frost. It has large rose-colored flowers that can be produced over the year. It hybridizes readily with other species, and its breeding potential is being explored.
Section Camellia (red camellias)
C. azalea, C. chekiangoleosa, C. crassissima, C. edithae, C. hongkongensis, C. japonica var. japonica, C. japonica var. rusticana, C. mairei, C. phellocapsa, C. pitardii var. pitardii, C. pitardii var. yunnanica, C. polyodonta, C. reticulata (according to Ming, 2000), C. saluenensis, C. semiserrata, C. subintegra, C. tenuivalvis, C. tunganica
Section Chrysantha (yellow camellias):
C. chrysantha, C. chrysanthoides, C. cuphuongensis, C. euphlebis, C. flava, C. impressinervis, C. liberofilamenta, C. nitidissima, C. petelotii, C. pingguoensis, C. tunghinensis
Section Eriandria: C. assimilis, C. caudata, C. cordifolia, C. lawii, C. salicifolia
Section Furfuraceae: C. crapnelliana, C. furfuraceae, C. gigantocarpa, C. octopetala
Section longipedicellata: C. indochinensis, C. longipedicellata
Section Luteoflora: C. luteoflora
Section Paracamellia: C. brevistyla, C. brevistyla form. rubida, C. fluviatilis, C. gauchowensis, C. grijsii, C. kissi, C. miyagii, C. obtusifolia, C. oleifera, C. sasanqua, C. vietnamensis, C. yuhsienensis
Section Piquetia: C. piquetiana
Section Protocamellia: C. granthamiana, C. yunnanensis
Section Pseudocamellia: C. henryana, C. trichocarpa
Section Thea: C. irrawadiensis, C. ptilophylla, C. sinensis var. assamica, C. sinensis var. sinensis, C. taliensis, C. vidalii
Section Theopsis: C. buxifolia, C. costii, C. cuspidata, C. euryoides, C. forrestii, C. fraterna, C. handelii, C. lancicalyx, C. longicarpa, C, lutchuensis, C. minutiflora, C. nokoensis, C. parvilimba, C. rosaeflora, C. transnokoensis, C. trichoclada, C. tsaii
Section Tuberculata: C. acuticalyx, C. anlungensis, C. parvimuricata, C. rhytidocarpa, C. rubituberculata, C. tuberculata
The material presented here is summarized by C. R. Parks from Collected Species of the Genus Camellia—An Illustrated Outline by J. Gao, C. R. Parks and Y. Du.