''Dioscorea elephantipes'', the elephant's foot yam or Hottentot bread, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the genus ''Dioscorea'' of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Dioscoreaceae,

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

to the dry interior of

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

Description

It is a

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

climber. It takes the name "elephant's foot" from the appearance of its large, partially buried,

tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...

ous stem or

caudex A caudex (: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is most ...

, which grows very slowly but often reaches a considerable size, often more than in circumference with a height of nearly above ground. This tuber can weigh as much as 365 kg. It is rich in

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...

, whence the name Hottentot bread, and is covered on the outside with thick, hard, corky plates. Primarily a winter grower, it develops slender,

leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leav ...

y, climbing shoots with dark-spotted, greenish-yellow flowers in winter (May or June in habitat) The flowers are

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, with male or female flowers occurring on separate plants.

Distribution

Its natural habitat is the arid inland regions of the Cape, stretching from the centre of the Northern Cape (where it occurs around Springbok), south to the Clanwilliam & Cederberg area, and eastwards through the districts of Graaff Reinet, Uniondale and Willowmore, as far as Grahamstown. It was recently rediscovered in a section of the Northern Cape Province by an expedition collecting seeds for the

Millennium Seed Bank Project The Millennium Seed Bank Partnership (MSBP or MSB), formerly known as the Millennium Seed Bank Project, is the largest ''ex situ'' plant conservation programme in the world, coordinated by the Royal Botanic Gardens, Kew, UK. After being award ...

. In this area, it is most common on rocky north & east-facing slopes, in quartz or shale based soils.

Cultivation

This species is not difficult to cultivate, however it requires extremely coarse, well-drained soil, and sparse watering. Importantly, it is deciduous and loses its leaves in the summer. At this time it goes through a dry dormancy period. It has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

Watering

This species indicates when it is requiring water, by the presence of green growth. From when a new growth appears from the thick stem (caudex), it can receive regular watering, up until the growth withers and dies back. This is when the plant goes into its summer dormancy. Then watering should become more rare – until the next new growth appears. The cycle can be extremely unpredictable or erratic, but in most cases this results in a watering regime of wetter winter and spring, and a dry summer dormancy period.

Sun and shade

In nature, the caudex is usually in shade beneath thicket vegetation, and only the leafy tendrils reach up to the sunlight. Therefore, the caudex is sensitive to prolonged exposure to heat and full sunlight, and a dappled-sun or semi-shaded position is preferable. The green vine tendrils however, thrive if they are able to reach partial or full sunlight.PlantZAfrica.com article
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Soil

This plant grows naturally in brush on rocky slopes, so it requires extremely well-drained soil, with a large (at least 50%) mineral component.

Temperatures

In cultivation in

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

areas, ''D. elephantipes'' can tolerate temperatures to −4 °C in habitat.

Gallery

File:Discoreaceae - Testudinaria elephantipes.JPG, Large tuberous stem File:Dioscorea elephantipes 03 ies.jpg, Leaves File:Testudinaria elephantipes montana1.jpg, Flowers

References

* {{Taxonbar, from=Q3023510 Crops originating from Africa Root vegetables Endemic flora of the Cape Provinces elephantipes Caudiciform plants House plants