Family: Apocynaceae
Habitat: Arabian Peninsula and Africa
Cultivation: Easy: Semi-shaded positions, warm temperatures and an attention to the dormancy period of the species regarding the irrigation.
Curiosity: The name Raphionacme is derived from the Greek words ‘rhaphys’, beet-root, and ‘akme’, sharpness, presumably describing the taste of the tuberous roots.

KEY FEATURES

Raphionacme is a genus of around 36 herbaceous or shrubby plants belonging to the Apocynaceae family. The name Raphionacme is derived from the Greek words ‘rhaphys’, beet-root, and ‘akme’, sharpness, presumably describing the taste of the tuberous roots.

Raphionacme are mainly found in Africa and Arabian Peninsula. Their habitats are extremely diverse: they often grow, however, often in woods or either in fissures of rocks, or either in open, dry areas, in alkaline or ferruginous soils, lowland grass-lands and savannas: it depends on the species. Also every species has a really wide area of distribution.

It includes herbaceous plants or shrubs, perennial thanks to the presence of subterranean tubers. Many species produce a white or colorless latex. Many of them, however, including the most sought after by fans of gardening and ornamental plants, are caudiciform herbaceous plants. A caudiciform plant is a plant equipped with a caudex. A caudex is an evolutionary device typical of semi-arid areas and used as a stock for nutrients and water to face harsh conditions of dry environments. In some species, the caudex can be huge: in R. velutina, for example, its diameter reaches a length of more than 30 centimeters!

The stems of Raphionacmes usually grow in erect, hairy tufts sprouting from the top of the caudex. They can be cylindrical or flattened, hairy or grablous, are often unbranched, and in some species they turn into vines.

Leaves are arranged in an alternate or opposite position along the stems, their shape is usually elliptical, more or less obovate or linear-lanceolate depending on the species. They are always bright green and, in some species, the ones of the lower pair are reduced to scales.

Flowers of Raphionacme are particularly cute. They sprout in June-July and are five-petaled and star-shaped. Actually, the petals are fused together in a tubular corolla and, for this reason, they are called lobes. The corolla lobes can show different colors: from green to, pale yellow, to the bright pink of Raphionacme splendens. They are flashy however being not so big: the corolla lobes reach 2,5 centimeters in length.

Flowers end up to form a kind of fruits called follicles. A follicle, in botany, is a dry unilocular fruit formed from one carpel (which is the organ forming the ovary of the flowers), containing two or more seeds. Raphionacmes usually have fusiform follicles, able to open when ripen to spread their seeds.

Raphionacmes are widely used, either for medical and for food uses. In many species in fact the large tuber is edible (for example, R. splendens), particularly rich in carbohydrates and poor in proteins. It’s more refreshing than nutritious. In fact, in another species called R. velutina, it is used as a source of water in dry months. The decoctions obtained by the leaves is used as eye drops to treat conjunctivitis.

VARIETY AND TYPES

Here below are the 36 accepted species of Raphionacme:

• R. angolensis
• R. arabica
• R. borenensis
• R. brownii
• R. caerulea
• R. chimanimaniana
• R. dyeri
• R. elsana
• R. flanaganii
• R. galpinii
• R. globosa
• R. grandiflora
• R. haeneliae
• R. hirsuta
• R. inconspicua
• R. keayi
• R. lanceolata
• R. linearis
• R. longifolia
• R. longituba
• R. lucens
• R. madiensis
• R. marcorrhiza
• R. michelii
• R. moyalica
• R. namibiana
• R. palustris
• R. procumbens
• R. pulchella
• R. splendens
• R. sylvicola
• R. utilis
• R. velutina
• R. vignei
• R. villicorona
• R. welwitschii
• R. zeyheri

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TIPS FOR GROWING

Raphionacmes can be grown from anyone to make wonderful bonsais, perfect as houseplants. Here below are our cultivation tips:

• Put your Raphionacme in a semi-shaded position, with their caudex at least partially exposed to avoid rotting (to unbury them will be sufficient).
• Raphionacmes don’t like cold. Keep them at temperatures above 12ºC in Winter. Some authors suggest that they can even stand short frost, if the soil is kept completely dry and the plant is protected from Winter rains.
• When the plant enters dormancy, the stems dry up and can be removed to maintain a tidy appearance.
• Irrigation throughout the year depends on the origin of the species: Summer growing ones need to be watered regularly in summer (aways waiting for the soil to dry up before each watering), rather more sparingly in Autumn and maintained completely dry in Winter. Winter growing species, on the contrary, need to be watered in Winter and maintained dry in Summer. If you’re uncertain whether your Raphionacme is a Summer or a Winter grower, just observe the moments when the stems dry up and then sprout again: if they sprout in Spring, your plant is a Summer grower.
• Repotting is rarely necessary as these plant grow very slowly.

The propagation of Raphionacmes can be carried out either by cuttings or by seeds.