Café marron (Ramosmania rodriguesii)

Description

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Café marron fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Café marron description

On sending his pupils out to explore for rare and interesting plants, a school teacher on the island of Rodrigues in 1980 was astounded when one of his pupils returned with a fresh cutting of a plant believed to be extinct ^{(2) (4)}. The plant was the café marron, one of two congeneric tree species bearing the same common name, both of which had last been seen in the 1940s. The café marron grows as a shrub or small tree, with oppositely arranged leaves that exhibit two very different forms on the same individual plant. While the juvenile leaves are linear, or narrowly elliptic in shape, and can reach up to 30 cm in length, the adult leaves are usually half as long and have a more broadly elliptic profile. The sweetly-scented, hermaphroditic flowers are greenish-yellow at first but become pure white at maturity ⁽²⁾.

French

Café Marron.

Size

Height: 2 - 4 m ⁽²⁾

Café marron biology

Like many plants with hermaphroditic flowers, the café marron is self-incompatible ⁽²⁾, meaning that the pollen from the flowers of an individual plant cannot fertilise the pistils of its own flowers ⁽⁵⁾. This common strategy prevents plants from inbreeding, whilst promoting out-crossing, which increases the genetic vigour of offspring ⁽⁵⁾. However, the inability to self-fertilise becomes somewhat less advantageous when a plant’s global population is reduced to a single individual.

Café marron range

The café marron is endemic to the island of Rodrigues, Mauritius, where it is presently known from just a single wild individual ^{(2) (4)}.

Café marron habitat

Historically known from tropical, humid forest ⁽²⁾.

Café marron status

Classified as Critically Endangered (CR) on the IUCN Red List ⁽¹⁾

Café marron threats

Along with much of Rodrigues’ native vegetation, it was probably a combination of introduced herbivores, invasive alien plants, and habitat loss that decimated the café marron population ⁽⁶⁾. Indeed, goats had reduced the remaining wild specimen to a small, half-eaten shrub when it was first discovered. Owing to the unprecedented level of scientific interest that surrounded the little plant in the aftermath of its re-discovery, local people became convinced of the plant’s medicinal properties ⁽²⁾. Consequently, there was a period before the erection of multiple fences ^{(1) (2)}, and even the installation of a guard, when people were intent on removing branches, twigs and leaves from the hapless plant ⁽⁷⁾. Although the protection of the single wild specimen has now been secured, the real obstacle to the species’ long-term survival is establishing an efficient means of propagating a non-sterile population from an effectively sterile plant ⁽²⁾.

Café marron conservation

Relatively soon after the re-discovery of the café marron, cuttings from the surviving plant were sent to Kew Gardens in England. At Kew, scientists were successful in propagating clones of the plant from the cuttings but could not find a means of successfully fertilising the flowers in order to produce seeds ⁽²⁾. Then in 2003, a major breakthrough was made when researchers discovered a technique to bypass the plant’s self-incompatibility mechanism, resulting in the production of a small number of viable seeds ^{(2) (8)}. Since then, several seeds have been successfully germinated at a nursery on Rodrigues, with the aim of eventually re-vitalising a wild population on the island ⁽⁹⁾.

Find out more

To find out more about conservation on Rodrigues see:

• Mauritian Wildlife Foundation:
  www.mauritian-wildlife.org

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Glossary

Congeneric

Species belonging to the same genus.

Fertilise

In a flowering plant, the process of a pollen grain joining with the ovule (female egg cell). After fertilisation, the female parts of the flower develop into a fruit.

Hermaphroditic

In plants refers to flowers that possessing both male and female sex organs i.e. both male stamens and female ovaries.

Inbreeding

The breeding of closely related individuals. An inbred population usually has less genetic variability and this is generally disadvantageous for its long-term survival and success.

Out-crossing

The breeding of unrelated individuals. Out-crossing increases genetic variability and the health of individuals and populations. It is generally beneficial for the long-term survival and success of populations.

Pistils

The female reproductive organs 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).

References

1. IUCN Red List (March, 2009)
   http://www.iucnredlist.org
2. Royal Botanic Gardens, Kew. (2009) Pers. comm.
3. Royal Botanic Gardens, Kew (March, 2009)
   http://www.rbgkew.org.uk/whatsnew/ramosmania.html
4. Silva, N.F. and Goring, D.R. (2001) Mechanisms of self-incompatibility in flowering plants. Cellular and Molecular Life Sciences, 58: 1988 - 2007.
5. WWF (March, 2009)
   http://www.worldwildlife.org/wildworld/profiles/terrestrial/at/at0120_full.html
6. National Public Radio - The Little Coffee Plant that Wouldn't Die (March, 2009)
   http://www.npr.org/templates/story/story.php?storyId=5307047
7. Smithsonian National Museum of Natural History Plant Conservation Unit. (2003) Rare Mauritian Plant Produces Fruit. Biological Conservation Newsletter, 227: 1 - .
8. Mauritian Wildlife Foundation. (2007) Kew Gardens gives hope of survival for the café marron. Mauritian Wildlife Foundation Newsletter, 8: 1 - . Available at:
   http://www.mauritian-wildlife.org