Cape buttercup  (Sparaxis elegans)

Classified as Vulnerable (VU) on the Red List of South African Plants (4).

This attractive perennial plant is recognised by its distinctively patterned flowers, and by the flower’s coiling anthers, which are twisted around the style (5). Each stem bears up to five symmetrical flowers, which measure around four centimetres in diameter and have six petal-like tepals, with a short funnel-shaped tube at the centre. The flowers of Sparaxis elegans come in various shades of red, orange, salmon-pink or sometimes white, marked with yellow or purple (2) (3) (5), and have a ring of distinctive yellow and black markings near the centre. One of the most striking features of Sparaxis species is the floral bracts, which are dry, papery, and pale in colour, with brown streaks (5) (6). Sparaxis elegans produces a fan of somewhat fleshy, pale green, lance-shaped leaves from an underground storage organ known as a corm (1) (2) (3) (5) (6).

Sparaxis elegans is endemic to the Cape Floristic Region in the western Cape Province of South Africa, where it occurs in the Bokkeveld Plateau in the northwestern Cape, extending southward some 25 kilometres from Nieuwoudtville. The more common salmon-pink form is typically found in the Nieuwoudtville area, while the white-flowered form occurs in the south of the range, sometimes mixed with the pink (5).

Sparaxis species are restricted to the winter-rainfall region of southern Africa, with this species usually growing in light to heavy clay soils (5) (6).

Sparaxis elegans is a perennial species, producing flowers annually between August and September, during or soon after the main rainy season (3). The flowers are bisexual (contain both male and female reproductive parts) (1), and are pollinated by scarab beetles and tabanid flies (3) (7). Intriguingly, the distinctive dark marks on the flowers, known as “beetle marks”, are believed to serve to attract its beetle pollinators (6) (7) (8). As in other Sparaxis species, the fruit is a capsule, which contains an average of 24 to 30 spherical, hard, shiny brown seeds (1) (5) (6).

Sparaxis species have long been valued as garden and indoor plants due to their bright and colourful blooms, and many hybrids have been created (1) (6). However, the impacts on the wild population of Sparaxis elegans are unknown. The greatest threat to this species is the loss and alteration of its habitat. The species occurs in nutrient-rich clay soil which is the most productive agricultural land on the Bokkeveld Plateau, and more that 70 percent of its habitat has already been converted for crop cultivation. Six populations remain in fragments which are only marginally suited to cultivation, and are not currently declining. However, sporadic ploughing of natural vegetation for new crop fields still occurs, and habitat loss remains a potential threat (9).

The Cape Floristic Region is considered a global hotspot for biodiversity and is designated as a Global Centre of Plant Diversity and a World Heritage Site. As such, it is one of the most intensely researched floral regions in the world, with a number of conservation initiatives in place, and also contains a number of National Parks and protected areas (10) (11). Although these are not considered totally representative of the region’s full biodiversity (10), they may go some way towards helping protect Sparaxis elegans populations. Conservation initiatives underway in the region include the Working for Water Programme, which is attempting to remove alien plants, encourage the regeneration of natural vegetation, and protect watersheds (10) (12), and one population of Sparaxis elegans is also protected in the Nieuwoudtville Wildflower Reserve (9). With measures such as these, and a high level of interest and attention in the region, this striking plant will hopefully face a brighter future.

For more information on South African plants see:

• PlantZAfrica:
  http://www.plantzafrica.com/

• Conservation International: Biodiversity Hotspots - Cape Floristic Region:
  http://www.biodiversityhotspots.org/xp/hotspots/cape_floristic/Pages/default.aspx
• Biodiversity and Wine Initiative:
  http://www.bwi.co.za/index.asp
• UNEP-WCMC: Cape Floral Region Protected Areas, Western Cape and Eastern Cape Provinces, South Africa:
  http://www.unep-wcmc.org/medialibrary/2011/06/29/2823bc8a/Cape%20Floral.pdf