Dioscorea elephantipes

Dioscorea elephantipes

Elephant’s foot or Hottentot bread (Dioscorea elephantipes (L’Hér.) Engl., 1908) is a shrub species belonging to the Dioscoreaceae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Class Liliopsida,
Order Liliales,
Family Dioscoreaceae,
Genus Dioscorea,
Species D. elephantipes.
The term is basionym:
– Tamus elephantipes L’Hér..
The terms are synonymous:
– Dioscorea elephantopus Spreng.;
– Dioscorea montana (Burch.) Spreng.;
– Dioscorea testudinaria R.Knuth;
– Rhizemys elephantipes (L’Hér.) Raf.;
– Rhizemys montana (Burch.) Raf.;
– Testudinaria elephantipes (L’Hér.) Burch.;
– Testudinaria elephantipes (L’Hér.) Dickson;
– Testudinaria elephantipes Lindl.;
– Testudinaria elephantipes f. montana (Burch.) G.D.Rowley;
– Testudinaria montana Burch..

Etymology –
The term Dioscorea is in honor of the doctor, botanist and pharmacist Pedanio Dioscorides Anazarbeo (from Anazarbo, Asia Minor), who lived in the 1st century AD, known mainly as the author of the treatise On medical herbs.
The specific epithet elephantipes refers to the resemblance of part of the plant to the elephant’s foot.

Geographic Distribution and Habitat –
Dioscorea elephantipes is a plant native to the arid interior of South Africa.
It was recently found in an area of the Northern Cape Province by an expedition collecting seeds for the Millennium Seed Bank project.
Its natural habitat is the arid interior regions of the Cape, extending from the center of the Northern Cape (where it is found around the Springbok), south to the Clanwilliam and Cederberg area, and east through the Graaff Reinet districts, Uniondale and Willowmore, as far as Grahamstown, where it grows between 150 and 1,200 meters above sea level, in the arid regions of the karrhoid. It is found on rocks exposed to the elements, on stony and arid slopes, under the protection of thorny and succulent bushes such as Carissa haematocarpa (Eckl.) A. DC. together with several species belonging to the Gymnosporia, Rhus, Aloe and Crassula genera.
In this area it is most common on rocky slopes facing north and east, in quartz or schist-based soils.

Description –
Dioscorea elephantipes is a dioecious, shrubby, climbing, deciduous plant, which grows very slowly but often reaches considerable dimensions, often exceeding 3 m in circumference with a height of almost one meter from the ground and a maximum weight estimated at 365 kg.
It has a rounded and hemispherical stem (tuber called caudex) partially buried, unbranched, woody, with a hard but succulent consistency inside and covered on the outside by a thick grey-brown bark, which with age becomes deeply cracked in plates prominent polygonals.
In young specimens the surface of the tuber resembles the carapace of a turtle while in adult plants it divides into irregular pieces, similar to cork, and in its entirety resembles an elephant’s foot.
From the tuber of this plant, the twining aerial stems develop which can reach 10 m in height with alternate leaves, having whole to lobed (heart-shaped) leaves of a shiny green colour.
The flowers are made up of six identical elements (tepals), very small and yellow-green in colour, grouped in racemose spike-like inflorescences and appear, in the natural habitat, normally in May or June.
The female flowers have mustard-colored tepals and have a trilocular lower ovary.
The male flowers have stamens almost as long as the tepals, 6 in number, with oblong or globose, light yellow anthers carried by thread-like filaments.
Pollination is entomophilous by bees and bumblebees.
When mature, the ovary produces a 2.5 cm light brown capsule containing up to six seeds with a membranous wing.
The seeds are released in September and October. The plant in its natural environment goes dormant during the hot, dry summer and grows in the winter and spring months.

Cultivation –
Dioscorea elephantipes is a plant that takes its name because of its large, partially buried, tuberous stem. This is rich in starch, hence the name Hottentot bread, and is covered on the outside with thick, hard, corky slabs.
It is a dioecious plant, that is, with separate sexes, whose male and female flowers are produced on different plants.
It is an easy-to-grow plant, however it requires extremely coarse, well-drained soil and limited watering.
For its cultivation outside its range it is necessary to have a substrate with sand and clay granules. Since this plant grows naturally in bushes on rocky slopes, it requires extremely well-drained soil, with a large mineral component (at least 50%).
During the growing season, the plant should be watered when the substrate is dry and this operation should be done on bright, warm days to minimize the risk of rot. You must absolutely avoid letting water enter the point from which the new shoot will grow.
If the leaves are absent, during the summer rest period, watering should be reduced to a minimum or suspended. Fertilization should normally be done monthly, but in summer with a greater quantity of nitrogen and less potassium.
Being a winter growing plant, it should not be given water until it begins to show the first signs of vegetative growth. The caudex should be kept in shade or partial shade, while the leaves can be in full light in order to promote chlorophyll photosynthesis.
If temperatures remain above 5 °C, it is not necessary to hospitalize the plant. During the vegetative period if the temperature rises, the plant risks returning to dormancy with the loss of aerial shoots. In cold climate locations, the plants should be kept outdoors from mid-May to the end of September and then placed in a greenhouse with a temperature of 12-15 °C, and no higher, so that the environment is as cool as possible to maintain control over the populations of parasites such as scale insects, red mites and thrips.
This plant is propagated by seed and can be grown in terracotta pots to allow for more oxygen in the potting mix and also to ensure better drainage.
The seeds, which are winged, should be buried in shallow-bottomed containers, possibly on heated pallets, at a maximum depth of 4-5 cm. Germination is facilitated by indirect light.

Customs and Traditions –
Dioscorea elephantipes is a plant known by some names, including: elephant’s foot, Hottentot bread (English); Hottentot bread, elephant’s foot, tortoiseshell plant (Italian); pied d’éléphant (French).
The tuber of this plant contains very high levels of commercially valuable steroidal saponins such as diosgenin which is used as a basic molecule for the commercial synthesis of steroids such as cortisone, pregnenolone, progesterone and other steroidal products (e.g. birth control pills ).
Wild plants, in the past, have been subject to massive collection by unscrupulous collectors or by the indigenous “Khoikhoi” populations of southern Africa, called Hottentots by the Dutch, both for medicinal and food use. The latter use, however, requires long processing to remove the toxic compounds and therefore the tubers are now consumed only in times of famine.

Preparation Method –
Dioscorea elephantipes is a plant that is used, in its natural range, for both medicinal and food purposes.
In the past the tubers were eaten by the indigenous people of South Africa, after extensive processing to remove toxic compounds. Due to the great effort required to obtain edible material, nowadays such tubers are normally consumed only in times of famine.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora d’Italia, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/57493767/original.jpeg

Attention: Pharmaceutical applications and food uses are indicated for informational purposes only, they do not represent in any way a medical prescription; we therefore decline any responsibility for their use for healing, aesthetic or food purposes.