Codonanthe is a genus containing approximately 8 species found primarily in the montane and lowland forests of southeastern Brazil near the Atlantic Ocean. Codonanthe species are epiphytes with a trailing growth habit. They grow well in hanging baskets. Their ease of culture, small size, and ease of bloom make them easier to grow then other epiphytic gesneriads like Nematanthus, Columnea, and Aeschynanthus. However, their small, white blossoms are not as showy as the blossoms of those other genera.
Codonanthe is closely related to Nematanthus and Codonanthopsis. They are all within the same clade of Tribe Episcieae in the New World subfamily of gesneriads Gesneriodeae. More recent DNA testing from 2013 revealed that Codonanthe is more closely related to Nematanthus than to Codonanthopsis. Nematanthus and Codonanthe grow in the same geographic area, and they share the same number of chromosomes (2n=16). In comparison, Codonanthe and Codonanthopsis differ in their geographic locations, their number of chromosomes, the shape of their fruit, and the presence of corolla spurs, extrafloral nectaries, and anther connective tissue. Hybridizers have been able to create intergeneric hybrids between Codonanthe and Nematanthus, but there are no known intergeneric hybrids with Codonanthopsis.
The etymology of the name comes from the Greek kodon, which means “bell,” and anthe, which means “flower.” The name refers to the bell-shaped (campanulate) form of the blossoms.
Codonanthe grow well in a well-drained soilless mix and under a 2-lamp fluorescent light shelf. Higher humidity levels well over 50% would induce better flowering and fruit production. Codonanthe usually prefers lower temperatures than Codonanthopsis.
- Distribution. Codonanthe are found in the forests of southeastern Brazil off the coast of the Atlantic ocean.
- Growth Habit. Codonanthe are epiphytic. They have a growth habit as shrubs or herbs.
- Stem. The stem can grow upward, pendent, or creeping. The stem can be woody or woody only at the base, and it can have fibrous roots that grow from its nodes.
- Leaves. The leaves are opposite, and each leaf pair is typically of the same shape and size. The petioles are short, and the leaves are of a fleshy substance but can take on a tough, leathery texture when dry.
- Inflorescence. Mostly solitary with one flower per leaf axil. However, a couple of species have a cyme. Flowers are typically without peduncles or bracts. The pedicels are usually short.
- Sepals. The sepals can be somewhat equal or very unequal. The dorsal sepals are usually bent backwards.
- Corolla. The corolla is typically white, pink, lilac, yellow, or deep purple. It usually has reddish lines or spots. The corolla tube is smaller at the base and gradually widens similar to a funnel. (funnelform). Some species have corolla tubes that are slightly bell-shaped (campanulate). The base of the corolla can be rounded or broader toward the throat (ventricose). The lips at the end of the corolla are rounded and spreading. The corolla is usually erect in position to the calyx. There are no spurs at the base of the corolla.
- Male parts. Codonanthe has four stamens with filaments that are closely attached to the base of the corolla tube or fused to the base. The stamens are recoiled or lowered after the pollen is shed. The anthers are oblong in shape and are connected to each other in pairs by the tips or sides. The nectary is a single dorsal gland.
- Female parts. Ovary is superior. The stigma is bilobed or just a small single mouth (stomatomorphic).
- Fruit. Fruit is a berry that is yellow-orange to dark orange in color.
- Chromosome number. 2n = 16.
LIST OF SOME CULTIVATED SPECIES