Harpochloa falx

Description

Harpagophytum, also called grapple plant, wood spider, and most commonly devil's claw, is a genus of plants in the sesame family, native to southern Africa. Plants of the genus owe their common name "devil's claw" to the peculiar appearance of their hooked fruit. Several species of North American plants in the genus Proboscidea and certain species of Pisonia, however, are also known by this name. Devil's claw's tuberous roots are used in folk medicine to reduce pain. The ethnobotanical use of devil's claw originated in southern Africa. H. procumbens is one of the floral emblems of Botswana where it is thought to be useful in treating a variety of pain conditions. Preparations of the plant or its extracts, such as harpagoside, are presumed to have uses in folk medicine and phytotherapy as an anti-inflammatory herbal drug or dietary supplement. Although there is no accepted clinical evidence of its efficacy and bioavailability, limited effects were noted for treating lower back pain and osteoarthritis. A Cochrane review of clinical research noted that devil's claw seems to reduce low back pain more than placebo, although evidence was of moderate quality at best. Harpagophytum procumbens inhabits deep, sandy soils, and occurs in areas with low annual rainfall (150–300 mm/year). It is a perennial, tuberous plant with annually produced creeping stems. The above-ground stems emerge after the first rains and die back during droughts or after frosts. The stems grow from a persistent primary tuber and several secondary tubers (the harvested organs) grow from the primary tuber at the end of fleshy roots. The plant gets its scientific and common names from the hooked spines of its woody capsules (see photo). The mature fruit opens slowly so that, in a given year, only 20-25% of its seeds may establish soil contact. Seeds have a high degree of dormancy. They have a low respiration rate and may remain viable in the seed bank for more than 20 years.