Thaumatococcus is a small genus of tropical flowering plants in the family Marantaceae (the arrowroot and prayer-plant family), placed in the order Zingiberales. The genus is native to the rainforests of western and central Africa and was long considered monotypic, containing only Thaumatococcus daniellii; a second species, T. flavus, was formally described in 2012 from Gabon.
Thaumatococcus daniellii — the best-known member — is a large, rhizomatous perennial herb reaching 3–3.5 m in height, with broad ovate-elliptic leaves up to 60 cm long and 40 cm wide that emerge singly from rhizome nodes, giving the plant a lush, tropical appearance reminiscent of other large-leaved Marantaceae. The plant bears pale purple flowers in single or branched spikes and produces fleshy, trigonal fruits that ripen to dark red-brown, each enclosing up to three hard black seeds surrounded by a pale yellow basal aril.
The genus is of considerable economic and scientific interest because that aril contains thaumatin, an intensely sweet protein at least 3,000 times sweeter than sucrose by weight. Thaumatin is nontoxic and noncaloric and has been used commercially as a natural sweetener and flavour enhancer since the mid-1990s, with ongoing research into its potential as a healthier sugar substitute. The species is also deeply embedded in West African material culture: the sturdy leaves are used to wrap and cook foods such as moi-moi and ofada rice, the petioles serve as weaving material and building tools, and various plant parts have traditional medicinal applications across its range from Sierra Leone to the Democratic Republic of the Congo.
Etymology
The genus name Thaumatococcus derives from the Greek thaumat- ("wonder" or "miracle") combined with kokkos ("berry" or "seed"), alluding to the remarkable sweetness of the fruit's aril. The species epithet daniellii honours W. F. Daniell, a British army surgeon and naturalist who collected specimens in West Africa during the nineteenth century.
Distribution
Thaumatococcus daniellii is native to the tropical rainforests of western and central Africa, ranging from Sierra Leone in the west southeast through Gabon and into the Democratic Republic of the Congo; it has also been introduced to Australia and Singapore. The second species, T. flavus, is known from Gabon in central Africa.
Ecology
The genus grows in the understorey of tropical rainforest and requires shade; in full sun, plants suffer severe losses during the dry season. Vegetative growth is seasonal, with main flowering occurring at the start of the rainy season (March to August). Fruits form at or below the ground, and the duration from flower opening to fruit ripening averages approximately 13 weeks. Self-pollination is almost impossible, and plants must reach a minimum age before setting fruit.
Cultivation
Thaumatococcus daniellii is most reliably propagated from rhizome fragments bearing one or two stools, as seed germination rates are low and seedling growth is slow. Plants are typically spaced approximately 1 × 1 m under shade, and within a few months their foliage covers the ground and suppresses weeds. Main fruiting begins only after the first year. Fruits form at or below ground level, so harvesting requires searching in the substrate; regular defoliation for leaf harvest can reduce subsequent fruit yield. Irrigation during the dry season improves fruit output.
Cultural Uses
In West Africa, T. daniellii is used extensively for food preparation: the large leaves (called uma in Igbo and ewe eran in Yoruba) are used to wrap and steam dishes such as moi-moi, agidi, ofada rice and pounded yam, while the petioles are woven into mats or used as tools and roofing material. The fleshy aril of the fruit has long been used to sweeten palm-wine, bread and sour foods. Medicinally, the leaf sap is applied as an antidote to venoms and stings and as a sedative; the plant is also used as a laxative, emetic and remedy for pulmonary complaints in the Ivory Coast and Congo. Since the mid-1990s, the extracted sweetening protein thaumatin has been used commercially as a noncaloric natural sweetener and flavour enhancer in the food and confectionery industries.
