Devil's claw (Harpagophytum procumbens) flowers and fruit

Devil's claw -  Harpagophytum procumbens

Devil's claw (Harpagophytum procumbens) has nasty, spiny fruits but it is one of the chief medicinal plants southern Africa has given to the world. Its uses are multifarious and many tons of dried tubers are exported each year, mainly to Europe. Most of this is harvested in the wild so there has been much concern about over-harvesting. Efforts to get the plant into cultivation have not yet led to much success. 

Devil's claw is a prostrate, sprawling plant with a stout, perennial rootstock that has a group of secondary storage tubers arising from it. Trailing annual stems bear opposite leaves. These are irregularly 3–5-lobed and greyish green because they are covered in tiny whitish mucilage cells. 

Harpagophytum procumbens, also called grapple plant, wood spider and Devil's Claw. The name "devil's claw" is also used for several species of North American plants in the genus Proboscidea.

The flowers are trumpet-shaped and range in colour from dark velvety red or purple to pink while the tube base and mouth are yellowish; they can be all yellow, all purple or white. The very distinctive spiny fruits, from which many of the common names are derived, are woody, oval and flattened capsules armed with 2 central spines and 2 lateral rows of 12 – 16 horny arms bearing hooked spines.The many seeds are roughly oblong and dark brown or black. The plants flower mainly from about November to April (summer) and have fruits from about January. 

Devil's claw grows mostly in the savanna biome and is associated mainly with dry sandveld on deep Kalahari sand. It usually occupies plains, dune bases and interdunes. Soils are usually sandy but can be rocky. They are generally nutrient poor, often with lime. The plants can probably withstand some frost as they are geophytes, being dormant in winter. Distribution is often patchy. 

The fruits are well adapted for dispersal by animals as the hooks get caught in feet and hair or skin and are carried away. Eventually they wear down, or drop off and break open, releasing the seeds far from the parent. Sometimes the animals die of starvation as the fruits catch on mouths and cannot be dislodged. Wind may also help in dispersal and trampling will help bury the seeds. The secondary tubers are dug up and eaten by porcupines and antelope such as duiker and steenbok. 

Devil's claw has long been known as a medicinal plant, with the San of the Kalahari having used it first, many generations ago. A German, G.H. Mehnert, learnt about this plant from the San and Nama people in Namibia and let it be known in 1904. It was exported to Germany first, and a small industry developed, based on material mainly from Namibia and Botswana. 

The plant's large tuberous roots are used medicinally to reduce pain and fever, to stimulate digestion. European colonists brought Devil's Claw home where it was used to treat arthritis. 

World demand has risen a lot since 1962 and especially in this century. Devil's Claw is now claimed to be beneficial for treating various diseases

Namibia has exported 2000 t. of dried roots in a year that may have involved up to 50 million plants. 

The harvesters, of whom there are thousands, are almost all from very poor, rural communities living in near-desert conditions. They are mostly women, between 40 and 60 years old, who have little if any means of making a living and hence turn to harvesting devil's claw. This is despite the poor rewards for long hours and long distances travelled on foot. 

Source:
http://www.plantzafrica.com/planthij/harpagpro.htm