EPOW Ecology Picture of the Week -- "Macaroni" Plant of Central Africa

Explanation: During a trek into vast and remote Salonga National Park in the seasonally-flooded tropical forests of the interior Congo River Basin, I was shown this common but overlooked understory plant, and learned of its various uses.

This is Yoruba soft cane, a giant forest herb and a member of the arrowroot family (Marantaceae). It forms locally dense, head-high thickets in the understory of these tropical jungles.

Yoruba soft cane has shiny, very large leaves that gather the scant
sunlight that makes it to the forest floor through the dense canopy
overhead. The plant also occurs in small forest openings where
sunlight can more readily penetrate; there, it can delay
regeneration of trees and locally dominate openings.
It can also invade areas after logging, agriculture, and fire.
Its occurrence in dense, closed forests might be the result of prior
human disturbance caused by ancient openings and shifting agriculture.

In this week's main photo, we see local researcher and colleague Imari Ilambu showing me how the moist, unfurled leaf-stems of this plant can be gathered as food, locally called "macaroni" (perhaps humorously so).

Fresh leaves of Yoruba soft cane starting to unfurl.

The large leaves of Yoruba soft cane is most often used to wrap and transport food. It is said that the leaves impart a nice flavor to some food, and thus are preferred to banana leaves which are also used to wrap food. The leaves also are used as impromptu (and biodegradable) dinner plates, as we used them at a lunch rest stop during our forest trek.

The leaves are reported to be commonly sold in markets of Libreville, Republic of Congo, to be used to wrap food, typically cassava stick (manioc); there, Yoruba soft cane is called ngungu. It is a low-cost and relatively easily-obtained and high-value commodity.

Moreover, further uses of the plant include social, religious, and magical applications. The leaves are also useful as building materials. The leaves and fruits are used as medicine for venomous bites and stings. The semi-woody leaf stems are used to construct implements for farming, hunting, and fishing. This one plant provides such a great diversity of uses!

Pulp of the fruits can be used as food and medicine for stings and bites.

Left: The wide leaves are adapted to gather maximum light in the dim jungle understory.
Right: They are also used as food for some forest insects.

Yoruba soft cane has also been introduced to Hawaii as a cultivated plant.

Perhaps more importantly, the plant has been shown to be a common nest material used by western lowland gorillas in southwestern Central African Republic (see Fay 1989). Also, pygmy chimpanzees or bonobos have been shown to consume this species, along with other medicinal plants recognized and used by the Mbuti and Mongo-Boyela people of the area. The plant is also a major food resource for forest elephants in Odzala National Park in the Congo Basin.

Thus, if much of the forest-occurring Yoruba soft cane is the result of past forest clearing for agriculture and habitation by people, then it is clear that there is a form of commensalism occurring in the tropical forests of central Africa. People have provided the conditions for establishment of this plant, which in turns is used by primates and elephants ... and then again by people of the region. The benefits of this plant have thereby come full circle.

Information:
Fay, J. M. 1989. Partial completion of a census of the western lowland gorilla (Gorilla g. gorilla (Savage and Wyman)) in southwestern Central African Republic. Mammalia 53(2):203-216.
White, L.J.T. 2001. Forest-savanna dynamics and the origins of Marantaceae forest in central Gabon. In: Weber W., White L.J.T., Vedder A., and Naughton-Treves L., editors. African Rain Forest Ecology and Conservation. New Haven and London: Yale University Press.

EPOW - Ecology Picture of the Week