Riversdale bluebell (Gladiolus rogersii)

Kingdom	Plantae
Phylum	Tracheophyta
Class	Magnoliopsida
Order	Liliales
Family	Iridaceae
Genus	Gladiolus (1)
Size	Height: 30 – 60 cm (2)

Variety Gladiolus rogersii var. vlokii is classified as Rare on the Red Data List of Southern African Plants (3).

Scientifically named after Reverend Moyle Rogers, who first collected the species (4), the Riversdale bluebell bears pretty bell-shaped flowers at certain times of the year. The faintly fragrant flowers are shades of blue and purple, with yellow or white markings on the lower petals (2), and measure up to 35 millimetres long (4). The leathery leaves of the Riversdale bluebell are almost needle-like, and underground, food for the plant is stored in a swollen stem base (2) (5).

Endemic to the Cape Floristic Region, an area in south-western South Africa which is home to the highest density of plant species in the world. The Riversdale bluebell is distributed from Pearly Beach, east to Humansdorp (2).

The Riversdale bluebell inhabits sandstone and limestone slopes, up to 1,000 metres above sea level (2)

Between the months of September and October, the Riversdale bluebell is in flower (2), and the weak scent of the blooms attract bees, which carry out pollination. The shape of the flower readily accommodates the head and thorax of the bee, and as it climbs into the flower in search of a sip of nectar, it receives a dusting of pollen (6).

The Riversdale bluebell species is not yet known to be threatened, but the variety G. r. vlokii is classified as Rare, meaning that the population is so small an unexpected threat could cause a critical decline (3). It is known that urban expansion, the encroachment of agriculture, and the invasion of alien plant species pose a threat to the habitat of the Cape Floristic Region (7) (8), the area to which this variety is confined.

Within the Cape Floristic Region there are a number of protected areas (9), 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 (10), the removal of alien plants, and the establishment of new protected areas (7), measures which should hopefully protect the rare variety of the Riversdale bluebell from becoming seriously threatened.

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

• Wild Cape Nature Trust:
  www.wildcape.org
• Conservation International: Biodiversity Hotspots:
  www.biodiversityhotspots.org/xp/hotspots/cape_floristic

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk

• Cape Floristic Region: an area occupying about 90,000 square kilometres in South Africa that contains an incredibly high diversity of plant species (around 8,700 species), of which 68 percent are found no where else.
• Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
• Pollination: the transfer of pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.
• Variety: in taxonomy, the science of classifying organisms, variety is the rank below subspecies. Members of a variety differ from others of the same species in relatively minor ways.

1. Heywood, V.H. (1978) Flowering Plants of the World. Oxford University Press, Oxford.
2. Goldblatt, P. and Manning, J. (2000) Cape Plants: A Conspectus of the Cape Flora of South Africa. National Botanical Institute of South Africa, Pretoria .
3. Hilton-Taylor, C. (1996) Red Data List of Southern African Plants. Strelitzia 4. National Botanical Institute, Pretoria, South Africa.
4. Paterson-Jones, C. and Manning, J. (2007) Ecoguide Fynbos. Briza Publications, Pretoria, South Africa.
5. Allaby, M. (1998) Dictionary of Plant Sciences. Oxford University Press, Oxford.
6. Goldblatt, P., Manning, J.C. and Bernhardt, P. (1998) Adaptive radiation of bee-pollinated Gladiolus species (Iridaceae) in southern Africa. Annals of the Missouri Botanical Garden, 85(3): 492 - 517.
7. Conservation International: Biodiversity Hotspots (February, 2008)
   http://www.biodiversityhotspots.org/xp/hotspots/cape_floristic/Pages/default.aspx
8. Rouget, M., Richardson, D.M., Cowling, R.M., Lloyd, J.W. and Lombard, A.T. (2003) Current patterns of habitat transformation and future threats to biodiversity in terrestrial ecosystems of the Cape Floristic Region, South Africa. Biological Conservation, 112: 63 - 85.
9. UNEP-WCMC: Cape Floral Protected Areas of South Africa (February, 2008)
   http://www.unep-wcmc.org/sites/wh/pdf/CAPE%20FLORAL%20REGION.pdf
10. Fauna and Flora International (February, 2008)
    http://www.fauna-flora.org/fynbos.php