A group of about eighty species of evergreen trees and shrubs widely distributed in Asia. Leaves alternate, toothed, short-stalked. Flowers usually showy, often solitary or two, never more than a few together, either clearly stalked with two to five bracteoles distinct from the five persistent sepals or appearing sessile because the short pedicel is completely covered by a series of overlapping, usually deciduous bud-scales which represent bracteoles and sepals; petals five to twelve, usually firmly united to the androecium and falling with it, but sometimes free; stamens numerous, the outer united for at least a short distance at the base and usually much higher to form a distinct fleshy tube. Seeds large and oily, soon decaying.
The genus was named by Linnaeus after George Joseph Kamel, a native of Moravia and a member of the Society of Jesus. He latinised his name into Camellus and under it wrote an account of the plants of the Island of Luzon in the Philippines, which he had visited. This account John Ray included as an appendix to his Historia Plantarum, published in London in 1704.
Until the introduction of C. saluenensis, hybrids were unknown, but once that species became established hybrids were raised between it and C. japonica and C. cuspidata, and the success of these crosses has led to a surfeit of crossing with each and every species and hybrid in cultivation. A comprehensive list of hybrids is given in the American Camellia Year Book, 1966, pp. 113-42, and see also pp. 203-27. Camellia has become a favoured genus, especially in the United States and Australia, and in addition to various regional and national Camellia societies, which publish journals – the largest being The American Camellia Society – there is now an International Camellia Society which publishes a journal, while the Royal Horticultural Society produces annually a Rhododendron and Camellia Year Book. The standard work on the species is: J. R. Sealy, A Revision of the Genus Camellia, London, 1958, illustrated with numerous line-drawings.
All the camellias prefer a peaty soil, but will thrive in a warm, open loam, especially if leaf-soil and a little peat be given them to start with, and so long as the soil is lime-free. They can be increased by stem and leaf-bud cuttings of half-ripened wood inserted in a mixture of sand and peat in a propagating frame. Bottom heat is desirable but not essential. C. reticulata is an exception and should be grafted onto seedlings of C. japonica of suitable size.
From the Supplement (Vol. V)
In his A Revision of the Genus Camellia (1958), J. R. Sealy treated and classified eighty-two species and in a concluding chapter discussed a few others which for one reason or another were imperfectly known. Since the publication of that pioneering work, the number of named species in the genus has almost doubled, most of the newcomers having been described by Professor Chang in a monograph published in Chinese in 1981 and now available, with additions and amendments, in an English translation: Chang Hung Ta and Bruce Bartholomew, Camellias (1984). This work recognises some 200 species, grouped in a revised classification, with keys and numerous line-drawings. Most of the new species are described from recent collections in central and southern China, and while some are obviously distinct, many are closely related to those treated in Sealy’s Revision. The two works are not strictly comparable, since Professor Chang does not deal in detail with any of the horticulturally important species, as indeed Dr Bartholomew points out in his valuable preface.
Durrant, T. – The Camellia Story. Auckland, 1981. A very well illustrated general account by a New Zealand authority.
Feathers, D. L., and Brown, M. H. (eds). – The Camellia; its history, culture, genetics… . American Camellia Society, 1978.
Longhurst, P., and Savige, T. J. – The Camellia. Sydney, 1982. Fifty-three colour plates from paintings by Peter Longhurst.
Macoboy, Stirling – The Colour Dictionary of Camellias. Sydney, 1981. A fully illustrated and well researched book by an Australian horticulturist, with contributions by experts on the various groups.
Trehane, David – Camellias. London, 1985. A short guide to choice and cultivation, published in the new series of Wisley Handbooks.
- - Trehane Camellias. n.d. A commercial catalogue with colour illustrations and useful descriptions.
Treseder, N., and Hyams, E. – Growing Camellias. London, 1975.
Tuyama, Takasi (ed.) – Camellias of Japan. Osaka, 1968. Vol. 1, descriptions of cultivars in English; Vol. 2, colour plates.
The Rhododendron and Camellia Year Book of the Royal Horticultural Society ceased publication after 1971. But camellias still feature in its successor – Rhododendrons [year] with Camellias and Magnolias, published annually.
Doubleness in the flowers of camellia cultivars is the result of the conversion of individual stamens, or clusters of stamens, into additional petals or into petalodes (petaloids), which are of intermediate form. In Semi-double flowers there are extra rows of petals but a central boss of stamens is still present, as in C. × williamsii ‘Donation’ or C. japonica ‘Mars’. In Anemone-centred flowers the central boss is replaced by a cluster of petalodes, with or without stamens, clearly differentiated from the spreading petals, as in C. japonica ‘Elegans’.
In Paeony-form flowers (informal doubles) there is less or no differentiation between the outer whorls of petals, which are irregular in form and tend to the upright position, and the central mass of stamens and petalodes. Most cultivars of this type have flowers of what is termed ‘loose paeony form’, in which the parts are rather laxly arranged, in contrast to the ‘full paeony form’ flowers which tend to a firmer, convex shape and may lack visible stamens. But the difference between these categories is not very clear cut.
In Formal Double flowers as a rule no stamens are visible and the numerous petals are imbricated (or sometimes arranged in radial rows); but the central petals often tend to form a bud-like cluster, which may conceal stamens, or in the so-called Rose-Form Double flowers, eventually open to reveal the stamens.
Before the breeding behaviour of the species of Camellia had been studied in depth, some stated hybrid parentages were pronounced impossible on chromosomal grounds. But scientific research has shown that these doubts were unfounded. In this connection the investigations of William L. Ackerman are of great interest. He has shown, for example, that, contrary to what was once stated, the diploid C. saluenensis can be crossed with the hexaploid (sometimes triploid) C. reticulata, the offspring being mostly tetraploid (Genetic and Cytological Studies with Camellia and Related Genera, USDA Technical Bulletin 1427 (1971)).