Ramosmania rodriguesii (café marron)
Café marron is endemic to the island of Rodrigues, Mascarene Islands, where it is presently known from just a single wild individual.
About this Species
On sending his pupils out to search for rare and interesting plants, a school teacher on the island of Rodrigues in 1980 was astounded when one of them returned with a fresh cutting of a plant believed to be extinct. The plant was Ramosmania rodriguesii, which is commonly known as café marron in the Mascarene Islands. Ramosmania is a genus of two species, the other being R. heterophylla, both of which had last been seen in the 1940s.
Geography & Distribution
Café marron is restricted to the island of Rodrigues, in the Republic of Mauritius, where it is presently known from just a single wild individual, although a few plants have been repatriated into the wild by the Royal Botanic Gardens, Kew.
Flowers of Ramosmania rodriguesii (Image: Wolfgang Stuppy)
Café marron grows as a shrub or small tree, 2 to4 high, 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 corollas are greenish yellow at first but become pure white at maturity.
The flowers of café marron are self-incompatible, meaning that the pollen from the flowers of an individual plant cannot fertilise the ovules of its own flowers. This common breeding system prevents plants from inbreeding, whilst promoting out-crossing, which increases the genetic vigour of offspring. However, the inability to self-fertilise becomes somewhat less advantageous when a plant’s global population is reduced to a single individual.
Threats & ConservationMore Information
Juvenile plant of Ramosmania rodriguesii (Image: Wolfgang Stuppy)
As with much of Rodrigues’ native vegetation, it was probably a combination of introduced herbivores, invasive alien plants and habitat loss that devastated the café marron population. 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. Consequently, there was a period before the erection of multiple fences and even the installation of a guard, when people were intent on removing branches, twigs and leaves from the hapless plant. 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 (see above).
Relatively soon after the re-discovery of the café marron, cuttings from the surviving plant were sent to Kew. Kew staff were successful in propagating clones of the plant from a single cutting but could not find a means of successfully fertilising the flowers in order to produce seeds. Then in 2003, a major breakthrough was made when a horticulturist discovered a technique to bypass the plant’s self-incompatibility mechanism, resulting in the production of a small number of viable seeds. Since then, several seeds have been successfully germinated and grown on at Kew. Cross-pollination of these seedlings leads to abundant seed production. Some seed produced at Kew has been successfully repatriated and grown at a nursery on Rodrigues, with the aim of eventually re-establishing a wild population on the island.
Buds of Ramosmania rodriguesii (Image: Wolfgang Stuppy)
Locals on Rodrigues believe that a tea made from the leaves of café marron is an invigorating drink that can treat venereal diseases and hangovers, although this has not been scientifically proven. An even more fanciful story is the ability of café marron to prevent children from having nightmares, but only if the child’s cuddly toy is thrown at the plant!
Millennium Seed Bank: Seed storage
Kew's Millennium Seed Bank partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.
Number of seed collections stored in the Millennium Seed Bank: 1
Open flower of Ramosmania rodriguesii (Image: Wolfgang Stuppy)
Café marron requires a tropical environment, with a minimum temperature of 18˚ْC and a maximum of 30˚C, and a relative humidity of 70 to 90% all year round. Propagation is easily achieved by apical cuttings of the main stem; the lateral branches cannot be used. Bottom heat and fogging in a misting unit considerably increase the rate of rooted cuttings, which are very slow to root. Partial shade produces handsome specimens when grown in the pots, but if planted in beds or in the open ground café marron can take full sun. Mealy bug and brown scale are the main pests of this species in cultivation.
This species at Kew
To find out more about conservation on Rodrigues see the Mauritian Wildlife Foundation website
More from the Kew website here
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