Cape speckled aloe  (Aloe microstigma)

Aloe microstigma flowering

Facts

Kingdom Plantae
Phylum Magnoliophyta
Class Liliopsida
Order Liliales
Family Liliaceae
Genus Aloe (1)
Size Height: up to 50 cm (2)

Status

Classified as Vulnerable (VU) in Namibia on the Southern African Plant Red Data Lists (3), and listed on Appendix II of CITES (1).

Description

The cape speckled aloe is an evergreen succulent plant (4), with a short stem and long, tapered leaves arranged in elegant rosettes (5). The leaves, measuring up to 30 centimetres long, are green to reddish, with white speckling and distinct spines along the margins (5). The scientific name of the cape speckled aloe refers to the white-flecked leaves, as microstigma means ‘little spot' in Greek (6). The flowers of this aloe species hang, nodding, on tall stalks, (up to 80 centimetres in length), and are either red, yellow or a mixture of both (5), giving an overall appearance of flames on an elaborate candelabra (7).

Range

Occurs in Namibia and South Africa (1), from the southern Western Cape to Albany in the Eastern Cape, and north through the semi-desert region of the Little Karoo, extending into southern parts of the Great Karoo (5).

Habitat

The cape speckled aloe grows on mountains and plains (3), on dry, stony, slopes amongst scrub (2) (6).

Biology

The cape speckled aloe produces its stunning flowers from June until August (2), which attract birds, particularly the southern double-collared sunbird (Nectarinia chalybea), to feed on its nectar. As it consumes the nectar, pollen is deposited on the bird, which results in the pollination of the next plant on which it feeds. In this manner, insects may also be responsible for pollination. The male and female reproductive organs (stamens and pistil) within each flower ripen at the same time, but aloe plants cleverly avoid the possibility of self-fertilisation as the stigma is able to recognize its own pollen, and only accept pollen from other plants (8). Following pollination, an abundance of small, black seeds develop that, with their tiny ‘wings', are dispersed by the wind.

Under the hot South African summer sun, the cape speckled aloe has evolved to remain relatively cool; the rosette arrangement of the succulent leaves means that the lower leaves are shaded from the sun by the upper leaves. In addition, during the summer months the leaves fold inwards, protecting the younger and softer leaves from the heat (7).

Threats

The cape speckled aloe is not considered to be threatened in South Africa, and is exceptionally common in the Little Karoo (6). However, in Namibia this species has been classified as Vulnerable to extinction as a result of mining, which degrades suitable habitat, and collection (3).

Conservation

The cape speckled aloe occurs within the Cape Floral Kingdom, a ‘hot-spot' of plant diversity in which there are a number of protected areas (9). This species is also listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this species should be carefully monitored (1). Hopefully this should help mitigate the threat of collection to the cape speckled aloe in Namibia.

Shell South Africa is working with FFI and the Flower Valley Conservation Trust (FVCT) to help conserve part of the Cape Floral Kingdom, the world's most botanically rich habitat.Shell biodiversity banner

Further Information

For further information on the cape speckled aloe see:

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Glossary

Cape Floral Kingdom: 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.
Pistil: The female reproductive organ of a flowering plant; consisting of a stigma (the pollen receptor), style (a stalk connecting the stigma with the ovary below), and ovary (encloses the ovules).
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.
Stamens: The male reproductive organs of flowers. A stamen is comprised of an anther (the pollen-producing organ) and a filament (stalk).
Stigma: The receptive part of the female reproductive organ of a flower. Pollen germinates on the stigma.

References

  1. CITES (February, 2008)
    http://www.cites.org
  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. Golding, J.S. (2002) Southern African Plant Red Data Lists. Southern African Botanical Diversity Network Report No. 14. SABONET, Pretoria.
  4. Heywood, V.H. (1978) Flowering Plants of the World. Oxford University Press, Oxford.
  5. Court, D. (2000) Succulent Flora of Southern Africa. A.A. Balkema, Rotterdam, Netherlands.
  6. Paterson-Jones, C. and Manning, J. (2007) Ecoguide Fynbos. Briza Publications, Pretoria, South Africa.
  7. PlantZAfrica (February, 2008)
    http://www.plantzafrica.com/plantab/aloemicrostig.htm
  8. The Private Life of Plants (BBC 1995)
  9. UNEP-WCMC (February, 2008)
    http://www.unep-wcmc.org/sites/wh/cape_floral.html