The Characteristics of Tropical and Rare Golden Camellias and Their Introduction

WANG Zhong-lang*  SHEN Yun-guang  FENG Bao-jun
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204

Introduction

The genus Camellia belong to the family of Theaceae, which has relatively more species and primitive in systematic, mainly distribute in Asia, and China has more than 80% of total species in the world^[1]. Many plants in the genus Camellia has important economic value, including the tea plant C. sinensis which is one of three beverages in the world, the woody oil plant C. oleifera which is called as oriental olive tree, and the famous ornamental flower, like C. japonica, C. reticulata and C. sasanqua ^[2].

The Camellia Garden of Kunming Botanical Garden is the oldest camellia specialist garden in China, has most complete cultivar collections of C. reticulata, and has been becoming the most important place for Kunming citizens to appreciate the city flower. In February of 2012, Kunming Botanical Garden was recognized by International Camellia Society as one of International Camellia Gardens of Excellence ^[3].

1 Characteristics of Golden Camellias

Golden camellias refer to the camellias with yellow flowers. In horticulture, golden camellias have become the fourth kinds of ornamental camellias, behind C. japonica, C. sasanqua, and C. reticulata. In the recent year, many related research were carried out, their international influence was increased greatly. These kinds of camellias have many characteristics, here just listed the most important four as follows:

1.1 Yellow flowers

Camellia is one of top 10 ornamental flowers in China, is the city flower of Kunming, is ranked as the top of eight most famous flowers in Yunnan Province. Camellia is also the famous flower in the world, and has a high reputation in horticultural world. However, cultivated camellias had only cultivars with white to red flowers before 1970s. Hu in 1965 published a new species Theopsis chrysantha in Plant Systematic Journal^[4]. Tuyama in 1975 moved this species to the genus as Camellia chrysantha^[5], which immediately made a stir in the world and become as important object for researching and breeding in camellia circle. Camellia chrysantha was then becoming one of the first class protected plants in China in the beginning of 1980s, and was called as the panda in plant kingdom. After that, around 35 yellow camellias were discovered in Guangxi, Guizhou and Yunnan of China and the north of Vietnam. Golden camellias have become one of most important groups in the genus Camellia.

1.2 Relatively narrow distributed area

Compared to other groups in the genus Camellia, most golden camellias mainly distributed in very narrow area from south Guangxi of China to north of Vietnam^[6]. Many species in Guangxi are only distributed in one or two townships, has a saying that ‘one species endemic to one mountain’, the endemic phenomenon is very obvious. Some other species with yellow flowers have very narrow distributed area. The species C. liberfilamentais only distributed in Ceheng of Guizhou Province, and the one C. szechuanensisis only distributed in Gulin of Sichuan Province, while the spicies C. fascicularis is only found in Hekou of Yunnan Province. Some species derived from North Vietnam have also very narrow distributed areas, such as C. hakodae, C. cucphongensis and C. tonkinensis etc.

1.3 High temperature and high humidity environment

In nature, golden camellias are mainly distributed in lower hills, bench terrace, valleys, brook-sides and limestone area with an altitude of 50-650 m, especially in the green broad-leaf forest with an altitude of 120-350 m. Compared to other species in the genus Camellia, golden camellias mostly favor the environment with high temperature and high humidity. So, if introducing these plants to Kunming, we need to put them in the glasshouse to satisfy their demands, especially in dry season in winter.

1.4 Divided into two kinds of soil and limestone

According to Liang’s investigation ^[6], golden camellias could be divided into two kinds, one is soil kind, the other is limestone kind. The species in soil kind were only distributed in red soil or brick red soil with pH 4.5 to 5.5, while those in stone kinds were only found in calcium soil in limestone hill with black or brown limestone soil with pH 6.5 to 7.5. In nature, no golden camellia was found both in red acid soil and also in limestone soil. But in cultivated environment, the plants originally in limestone area could grow in acid soil as well.

2 The construction of glasshouse for conservation of golden camellias

The glasshouse in camellia garden is the oldest glasshouse in Kunming Botanical Garden, was built in the beginning of 1950s. Integrated the improvement of camellia garden, we carried out the realignment of some paths and landscape inside the glasshouse, in order to construct a glasshouse conserving tropical camellias, especially yellow camellias. According to the characteristics of golden camellias and the climate of Kunming, we built a large area with water (pond and waterfall) to increase the humidity indoors (Fig. 1). As shown in Fig. 1, the humidity inside could exceed 80%, greatly higher than that in outside with 40-50%, the temperature could maintain 20 to 30 degree in Celsius. The environment is suitable golden camellias to grow.

Fig. 1 The comparison of temperature and humidity indoors and outdoors

Local Kunming soil mainly belong to red soil, added some limestone from southeast Yunnan, to build the cultivation condition and indoor landscape for growing golden camellias (Fig. 2).

Fig. 2 Newly built a limestone waterfall with 2.5 m high and a pond with 13.0 m X 1.5m,
increasing the indoor humidity and changing the flat landscape to three-dimensional vision.

In the construction of the landscape, the demand of tropical camellias was fully considered, especially the conditions on soil and temperature as well as humidity, the afterwards management and cost were also considered. In 2012 more than 200 members of International Camellia Society had visited the glasshouse, and praised the house good to local climate and low cost of management which was very suitable for golden camellias to grow.

3 The introduction and conservation of golden camellias

Golden camellias are mainly distributed in south Guangxi and north Vietnam. Our botanical garden had some collections on Chinese species, but the number had still gap. In recent years, through investigation and exchange, most Chinese species were collected. Five species in Vietnam were collected by the help of some friends in Vietnam. So far the glasshouse has become a house with international influence for conservation of golden camellias.

C. cucphoungensis	C. quephongensis

Fig. 3 Two golden camellias in Vietnam

C.micrantha	C.chrysantha
C.longgangensis	C. pubipetala

Fig. 4 Some golden camellias from Guangxi, China

4 Discussion and suggestion

4.1 Breeding new cultivars

In order to better use these precious golden camellia resources, the main task is to breed new cultivars with intellectual property. Since the glasshouse was finished at the end of the year 2011, we had carried out many controlled pollination, like very special C. chuongtsoensis with unusual flowering season as one of parents, the fruit set was quite high, this result indicated that the glasshouse is very suitable for golden camellias to grow from one side of view. The glasshouse provides good condition for breeding both in parent materials and in temperature and humidity condition.

4.2 Enhance the co-operation with Vietnam

Although Vietnam is neighboring country of China, in the field of investigation for camellias in Vietnam, Japanese camellia specialists had done a lot before us. In the past twenty years, Japan’s Kirino and Hakoda went to Vietnam several times a year, and had published some new species native to Vietnam. We need to enhance the co-operation with Vietnam in camellia researches.

Literature cited

[1] Ming Tien-lu, 2000.Monograph of the genus camellia. Yunnan: Yunnan Sci.& Tech. Press.
[2] Zhang Lechu, You Muxian, Chen Desong, et al, 2003. China Camellia Culture. Shanghai: Shanghai Culture Press.
[3] International Camellia Society website:http://www.internationalcamellia.org
[4] Hu X.X, 1965. Theopsis chrysantha Hu. Act. Phytotax. Sin. 10(2): 139
[5] Tuyama, 1975. Camellia chrysantha (Hu) Tuyama. Journ. Jap. Bot. 50(10): 299
[6] Liang Shengye, Lu Minzhu, et al, 2005. Yellow Camellias of China. Beijing: China Forestry Press
[7] Hakoda, N and S. Kirino. 1998. Species of genus Camellia in Vietnam. Jour. Jap. Camellia Society. ‘Tsubaki’ 37:22-30
[8] Ninh, T and N. Hakoda, 1998. Three new species of the genus Camellia from Viet Nam. International Camellia Journal, 30:76-79
[9] Ninh, T. and Hokoda, N. 1998. Camellia petelotii: a species of yellow camellia from Vietnam. International Camellia Journal, 30:81-83
[10] Ninh, T. 1998. Camellia rosmanii: a new species of yellow camellia from Vietnam, International Camellia Journal, 30:72-75
[11] Ninh, T. 2003. Results of the study on yellow camellias of Vietnam, International Camellia Journal, 35:73-75

 * Author for correspondence: Professor, wang@mail.kib.ac.cn