The Kigelia africana, commonly known as the sausage tree, is a striking botanical specimen from tropical Africa. It is named for its distinctive, elongated, sausage-shaped fruits that hang conspicuously from its branches. Its unique appearance makes it a notable and intriguing feature in its native landscapes.
Identifying the Sausage Plant
The Kigelia africana is a medium to large tree, typically 6 to 20 meters tall, with some reaching 35 meters. It has a rounded, spreading crown and a stout trunk. The bark is generally smooth and grey, becoming flaky on older trees, and its branches often spread low, forming a broad canopy.
The sausage tree’s compound leaves are arranged alternately or in whorls of three to four, growing up to 50 cm long. Each leaf has three to six pairs of leathery, yellowish-green leaflets, often with a single leaflet at the tip. These oblong to elliptic-ovate leaflets, 7-20 cm long and 4-12 cm wide, have mostly smooth margins, though they can sometimes be slightly toothed. Their surface is shiny green on top and duller underneath, sometimes with fine hairs.
The tree produces unique, bell-shaped flowers in long, pendulous racemes that can extend several meters. These large, fleshy flowers, 5-12 cm wide, range from orange to deep reddish-purple, often with yellow veins. They bloom only at night, lasting a single night, and emit a strong, musky scent, sometimes described as unpleasant, to attract nocturnal pollinators.
The Kigelia africana’s most distinguishing feature is its fruit. These large, woody, sausage-shaped fruits hang from long, rope-like stalks, resembling oversized sausages suspended from the canopy. They measure 25 cm to 100 cm in length and up to 18 cm in diameter, typically weighing 5 to 10 kilograms, though some can reach up to 12 kg. The fruits ripen from green to greyish-brown, containing a fibrous pulp with numerous unwinged, oval, hard seeds. These fruits are indehiscent, meaning they do not split open to release seeds; instead, seeds are dispersed after the fruit falls and decays.
Where the Sausage Plant Thrives
The Kigelia africana is indigenous to a vast expanse of sub-Saharan Africa, with its natural distribution spanning from Senegal eastward to Eritrea and southwards to South Africa. This wide geographical range highlights its adaptability to diverse African landscapes.
The tree flourishes in specific environmental conditions, predominantly along riverbanks, floodplains, and streams, where moisture is consistently available. It also grows well in open woodlands, savannas, and shrublands, often in deep, alluvial soils.
The sausage tree requires tropical and subtropical climates with distinct wet and dry seasons. It tolerates temperatures from 4°C to 40°C and thrives with 800 mm to 2000 mm of annual rainfall. Found from sea level up to 3000 meters, established trees endure moderate droughts, but young plants need frost protection.
Ecological Role and Traditional Significance
The Kigelia africana plays a role in its native ecosystems through unique pollination and seed dispersal. Its bell-shaped flowers bloom at night, emitting a strong, musky scent adapted for bat pollination. Hawkmoths and certain birds also visit the flowers for nectar.
The large, woody fruits contribute to seed dispersal, primarily through consumption by large animals. Elephants, baboons, monkeys, bushpigs, and porcupines eat the fruits, breaking their tough exterior to release seeds. The tree’s distribution along watercourses also suggests water plays a role in seed dispersal.
The Kigelia africana holds significant cultural and traditional importance across African communities. Its fruit, bark, roots, and leaves are widely used in traditional medicine for various ailments. These include skin disorders like ulcers, sores, eczema, and fungal infections, as well as wounds, gynecological issues, rheumatism, dysentery, and fevers. The tree’s tough wood is also used for crafting items like shelving, fruit boxes, and dugout canoes. Some communities regard the tree as sacred, holding religious meetings beneath its canopy.
Important Considerations
The Kigelia africana fruits are generally unsafe for raw human consumption. Raw fruits are poisonous, acting as a strong purgative and potentially causing mouth and skin blistering due to certain compounds.
While raw consumption is hazardous, traditional preparation methods can render the fruit edible or extract beneficial properties. Some communities dry, roast, or ferment the fruit, often to flavor beer or as a food source. The seeds can also be roasted and eaten. However, these methods require specific knowledge and are not recommended for the average person due to the raw fruit’s toxicity.
Beyond its traditional uses, the sausage tree is valued as an ornamental plant in tropical and subtropical regions for its decorative flowers and unusual fruits. Despite its appeal, its invasive root system and heavy falling fruits require careful consideration when planting near structures or vehicles. The fruit’s primary value, outside of traditional preparation, is in commercial products like skincare and cosmetics, where extracts are processed for beneficial compounds.