Thyme-leaved buchu  (Agathosma thymifolia)

Classified as Near Threatened (NT) on the Interim Red Data List of South African Plant Taxa (3).

The thyme-leaved buchu belongs to Rutaceae family, a group of aromatic trees and shrubs, sometimes known as the citrus family (1). The thyme-leaved buchu is a single-stemmed shrub that branches near ground level, and grows to form a rounded bush. The leaves are narrow ovals (2), and when crushed, produce a mild aroma from the oil glands that can be seen as small, translucent, black dots on the leaves (1). The small pink or mauve flowers (eight millimetres wide), grow in loose clusters at the tips of the branches (4), and the fruits are small berries (2).

Endemic to the Cape Floristic Region, a ‘hot-spot’ of plant diversity in south-western South Africa; from Vredenburg to Yzerfontein (2).

The thyme-leaved buchu has fairly specialised habitat requirements (5), growing only on coastal sand and dunes on limestone (2).

The thyme-leaved buchu flowers from August until October (2), and like other species of the Rutaceae family, it is likely to be pollinated by insects (1).

This aromatic plant is threatened by the encroachment of agriculture into its habitat, and habitat degradation (3). Cultivation for agriculture has transformed almost 26 percent of the Cape Floristic Region and 1.6 percent is now covered by urban areas (6). The spread of invasive alien plants also threatens to alter the unique, natural habitat of the Cape Floristic Region (7), to the detriment of many plant species. The thyme-leaved buchu may be more vulnerable to such threats than some other species, due to its specific habitat requirements.

The Cape Floristic Region contains nearly 9,000 plant species, most of which are found no where else in the world. This unique area is valued for its incredible diversity in plants, and thus there are a number of protected areas (8), and a number of conservation organisations are working to conserve this botanically rich habitat. Conservation actions include purchasing land to protect it from the threats of encroaching agriculture and urban development (9), the removal of alien plants, and the establishment of new protected areas (7); measures which should help ensure a thriving future for the thyme-leaved buchu.

For further information on the Cape Floristic Region and its conservation see:

• Conservation International: Biodiversity Hotspots (February 2008)
  www.biodiversityhotspots.org/xp/hotspots/cape_floristic