Through millennia of isolation, the Mascarene Archipelago has evolved a unique and rather fascination flora. However, just after a few centuries of being discovered by the first European explorers that navigated the area, its distinctive biodiversity was seriously eroded through habitat destruction, introduction of exotic but invasive species and the associated extinctions that followed. As an example, just in the Island of Mauritius itself there are more that a hundred species that are left with populations of less than 20 individuals or/and found in just one or two small localities.

Rodrigues Island is the smallest and, perhaps, the youngest of the Mascarene group, where at least eight species of vascular plants are already extinct, and, of the 38 surviving endemic species, 21 are endangered, of which at least 10 survive in populations smaller than 20 specimens. When Leguat visited the Island in 1708 he described the “paradisiacal qualities” of this isolated world. Years later in 1887, Balfour stated: “The Island is covered with a vegetation of mainly of social weeds, and destitute of any forest save in unfrequented and inaccessible parts.”

Ramosmania is a genus in the Rubiaceae (coffee family) endemic to Rodrigues Island, which is represented by one or possibly two species, Ramosmania heterophylla and R. rodriguesii. This genus has been always known for being elusive in many ways. Until recently no specimens had been found since 1940 and, after several searches, it was feared extinct. But suddenly, in the mid 1980s, a single specimen was discovered by a schoolboy, Hedley Manan, who had been encouraged by his teacher, Raymond A-Keeh, to search for rare plants. Since its rediscovery in the mid 1980s, the remaining wild tree has never set seed and the plant was continuously being cut by locals, and up to three concentric fences where erected to prevent vandalism. Some locals believed that the plant can treat hangovers and venereal disease, referring to it as “Café’ Marron” (French for “wild coffee”).

Then in 1986, in a collaboration between a local conservationist, Wendy Strahm, IUCN, Kew and the Mauritian Forestry Service, cuttings were flown to Mauritius and then on to London in the hope of saving this important endemic plant by growing it ex situ at Kew. Two lateral braches were sent to the Micro-propagation Unit, and a single apical cutting to the Temperate Nursery. Tissue culture failed to establish as all plant tissues carried a fungus that invades the culture media. However, the cutting sent to the Temperate Nursery was successfully rooted by Dave Cook, resulting in the first ex situ propagation of the species, from which dozens of cuttings were subsequently obtained. Many of these soon came into flower. 

However, I began to suspect that environmental factors were the real “detonator” that had overcome the supposed self-incompatibility. After testing many specimens in different glasshouse environments throughout Kew, a second fruit was developed and successfully harvested. Seeds from this second fruit were sown, and four weeks later four out of five seeds had amazingly germinated and where slowly growing. Once the suspected environmental parameters were trialed on a larger scale, it started to be obvious that we were on the right track to unlocking the mystery. Five years after the first fruit, more than 50 fruits have been produced at five different locations under the same peculiar environmental parameters that turned the Ramosmania styles to functional mode. Since then, more than 50 seedlings have germinated at Kew by traditional horticultural means and a series of beautiful saplings can now be observed. Fifty seeds and six saplings have been repatriated to the country of origin and Ramosmania rodriguesii happily germinated again on Rodrigues Island for the first time in, perhaps, more than 100 years. As a further insurance, seeds produced at Kew have now been stored in Kew’s Millennium Seed Bank at Wakehurst Place.

So what did the trick? Growing the plant almost touching the heating pipes of the glasshouse in a sunny location during winter makes the difference. In winter, because the heating goes on for long periods especially at night, and in a sunny location because then, in the milder sun of a British winter they will take all this extra “radiation” (from sun and the heaters) without melting them away or scorching them to death.

Several seedlings were then germinated using horticultural techniques and interestingly, the new progeny have very different and distinctive leaves from the adult plant. You would never recognize these saplings as belonging to this species unless you knew about this fact. This phenomenon, known as heterophylly, is very often found in the endemic flora of Rodrigues Island. I believe it may have evolved as an adaptation to avoid the grazing of the Rodrigues Giant Tortoise and the Solitarie, a terrestrial bird related to the Mauritian Dodo, both species nowadays extinct. The narrow juvenile leaves are harder to grab than the broad adult foliage developed on plants more than a metre (3 feet) tall. This is an adaptation to the grazing by billed animals rather than that of mammals which is accomplished by lips and teeth. What’s more, it is a form of camouflage. And unlike mammals, birds and reptiles don’t locate their food by the sense of smell and therefore, camouflage pays off.

Seed and seedling production, repatriation of genetically diverse seedlings, tissue culture and thereafter virtual cryopreservation of germplasm are not the only new hopes and possibilities for Ramosmania rodriguesii. Six years have passed since the first seedlings germinated at Kew and now several specimens have reached maturity, flowering for the first time in 2008 and revealing a fact that couldn’t be observed when comparing the few herbarium specimens with the only extant clone. Some of the new saplings bear a different type of flower: the new progeny has flowers with shorter corollas, longer stigmas and larger stigmatic lobes that rise well above the anthers (unlike the original surviving clone) and which so far don’t shed pollen.

This shows that Ramosmania is a dioecious species, but luckily the male flowers have female parts that occasionally can be triggered to the female stage (the female flowers have anthers but they don't shed pollen ...) and a few seeds were obtained by forcing the last specimen under controlled enviromental conditions. The seed produced led to the rise of few seedlings, genetically distinct and luckily some female plants. Pollination using pollen from the surviving clone and some of the newly grown males to one of its descendant female clone has led to fruits being developed, each bearing up to 85 seeds, that are larger than the ones set by the selfed male. This opens the door to possible “mass production” of seed and gives hope that, once and for all, Ramosmania can thrive and propagate itself back at home on Rodrigues Island, if a large scale reintroduction program were to be carried out.

With this aim I am currently in Mauritius and Rodrigues Island. Several saplings and propagations from the original clone flew with me in 2007 and now I’m supplying the country with many more saplings and more importantly +300 seeds, all genetically different and able to produce plants of both sexes. Further more, the planting back in the wild has started; I planted one on this trip. More will be planted on Biological Diversity Day. Something unthinkable for most of the 20th century has become part of history. This will be one of the few stories of plant conservation that may end up having a happy ending.