Camellia flower types
So called double flowers arise when the sexual organs of the flower (the male stamens or female pistils) mutate into petal-like structures (also known as petaloids). These extra ‘petals’ create a much fuller look to the flower and can create a number of different flower forms depending on the exact nature of the petaloids. A single or ‘wild type’ flower is one with only 5 to 8 petals in more or less a single row with numerous prominent yellow stamens in the middle of the flower. A semi-double flower has two or more rows of petals but still shows some yellow stamens in the centre of the flower while a double flower is one where the stamens are absent or almost so and are replaced by numerous extra petals. Fully double flowers in Camellia may be either formal with overlapping petals in a symmetrical arrangement or informal with petals arranged in a more or less random pattern giving a deeper flower structure. An anemone form Camellia has one or more rows of larger outer petals with a central mass of much smaller petals which form a convex ball which is sometimes interspersed with yellow stamens.
Camellia varieties that have arisen from mutations
Genetic mutations are changes that occur from time to time in the DNA of the chromosomes of living organisms. Such changes can occur throughout the life cycle of an organism and are caused by several factors such as high levels of gamma radiation or mutagenic chemicals or they may also occur spontaneously with no obvious cause.
Mutations result in many interesting effects such as variegated foliage, different coloured flowers or even a different plant habit as well as subtle changes that are not visually obvious. Mutations in plants that occur in vegetative growth (rather than in seeds) are often referred to as âbud sportsâ and in Camellias are relatively common and often start in the shoot tip of a single branch of the plant. Cuttings taken from such mutated branchs will usually stay true to the altered type and this is one of the ways in which new Camellia cultivars are created. Not all mutations are genetically stable and this is why you may see more than one flower colour or form on a single Camellia plant when odd shoots on the plant revert back to the original type.
Flower variegation in Camellias
Bicoloured flowers are also a feature created by genetic mutations. In such cases the flower can become spotted or striped, usually with white on pink or red flowers. In some cases the flower variegation is actually caused by infection with a virus rather than a genetic mutation.
Conventional Camellia breeding and its future directions
Most new Camellia cultivars arise from cross pollination of existing cultivars and/or wild species. This allows breeders to deliberately strive for particular breeding goals such as flower colour or size rather than the random improvements that arise unpredictably from mutations. For example the very popular Camellia x williamsii hybrid group resulted from a cross between various Japonica cultivars with a species Camellia saluensis, originally collected from mountainous regions of China, used in breeding initially in the 1920’s. This group of hybrids is especially noteworthy for its cold tolerance and ‘self cleaning’ flowering habit where the petals fall from the plant rapidly rather than staying put and turning an unsightly brown.
Current directions with Camellia breeding include an ongoing but thus far fruitless quest for yellow and orange flower colours through a group of buttercup yellow flowered wild species such as Camellia chrysantha. Fragrant species such a C. lutchuensis and C. oleifera continue to be used by breeders to create hybrids with sweeter and stronger perfumes.