Mauritiana coffee is Coffea mauritiana, a wild coffee species endemic to the forests of Reunion and Mauritius, where it is called cafe marron. It is a species in its own right, not a cultivar and not a selection of anything. It is not Bourbon. It is not Bourbon pointu. It has never been domesticated, it is not a commercial crop anywhere, and the consistent report from three centuries of people who have tried to drink it is that it is punishingly bitter.
That last point matters less than the first one. The single most useful thing this page can do is untangle a naming mess, because Reunion is the island that gave the world the Bourbon name, the island where the laurina mutant was selected, and the island where a genuinely low-caffeine wild Coffea species also happens to grow in the forest above the plantations. Three different low-caffeine-adjacent stories, one small volcanic island, and a great deal of coverage that runs them together.
Mauritiana coffee is a species, not a variety
Every expectation you carry from Geisha, Bourbon or SL28 has to be set down before reading further. Those are varieties, which are populations selected within the single cultivated species Coffea arabica. Mauritiana is a different organism at the species level, a separate branch of the genus with its own evolutionary history on islands that arabica never reached until humans carried it there. For the genus-level picture of how many Coffea species exist and how few of them are farmed, see our explainer on what the Coffea plant actually is.
Taxonomically, mauritiana is usually placed in the informal group called Mascarocoffea, a name applied to the Madagascan and Mascarene coffees, whose defining popular characteristic became the near-absence of caffeine in the seed. Molecular work has generally supported these island coffees as a related lineage rather than a random assortment, though the internal arrangement of species within it has been revised more than once and is better treated as live science than as settled fact. Madagascar holds the bulk of that wild diversity; our guide to Madagascar coffee covers that island's wild species, and mauritiana is best understood as the Mascarene outpost of the same broad radiation, one of a small number of Mascarene coffee species that stayed wild while arabica was carried around the world.
The practical consequence is genetic distance. Arabica is a tetraploid, carrying two sets of parental genomes from an ancient natural hybridisation. Mauritiana, like the overwhelming majority of Coffea, is diploid. The two are among the more distantly related members of the genus, and attempts to cross caffeine-free island coffees with cultivated species have run into documented sterility barriers. Where the two now grow on the same island they are neighbours, not relatives in any recent sense.
At a glance
| Item | What is reported |
|---|---|
| Name | Coffea mauritiana; local name cafe marron, sometimes cafe marron des hauts |
| Rank | A species, not a variety, cultivar or selection |
| Native range | Endemic to the Mascarenes: Reunion and Mauritius |
| Group | Traditionally placed in Mascarocoffea, the Mascarene and Madagascan island coffees |
| Habitat | Shaded understorey of humid upland forest; scattered patches, not stands |
| Elevation | A Reunion-wide genetic survey sampled it across roughly 270 to 1,500 m; treat that as a sampled range, not a hard limit |
| Plant | Shrub to small tree, reported to reach about 7 m; leathery, strongly veined opposite leaves with domatia in the vein axils |
| Flowers and fruit | Small, white, fragrant flowers in axillary clusters; a drupe like any coffee cherry, ripening brownish-yellow to purple depending on the account |
| Caffeine | Described as caffeine-free to trace-level; sources disagree on whether it is truly zero |
| Reported taste | Consistently described as sharply, aggressively bitter |
| Commercial status | Not a commercial coffee crop; the leaves have a local herbal-infusion tradition |
| Conservation | Listings differ: global databases commonly report Vulnerable, while at least one Reunion listing records Least Concern |
The Reunion naming mess, in three parts
Here is the disambiguation, laid out plainly. Three things on one island, routinely confused with one another:
1. Bourbon, an arabica variety group named after the island
Bourbon is a group of Coffea arabica varieties whose name comes from the island's colonial name. Nothing about it is wild and nothing about it is endemic; that story belongs to our Bourbon variety guide.
2. Laurina, or Bourbon pointu, a low-caffeine arabica mutant
Laurina is a distinctive, conical, pointed-bean arabica that appeared and was selected on the island, and it carries markedly less caffeine than ordinary arabica. It is still arabica, and our laurina guide covers its history and cup character.
3. Mauritiana, a wild species that was never domesticated
Mauritiana grew in the island's forests before either of the above arrived, and it is still there. It was never selected, never improved and never planted at scale.
The confusion is not accidental, and it has a documented history. Because the wild island species carries little or no caffeine, and laurina also carries less caffeine than typical arabica, it was once seriously proposed that laurina arose from a cross between introduced Bourbon arabica and the indigenous C. mauritiana. That hypothesis has since been tested against genetic markers and rejected: the marker profiles of laurina and Bourbon turned out to be nearly identical, far too close for a wide interspecific hybrid, and the explanation now favoured is a mutation arising within Bourbon itself, on an island where self-pollination and a small founding population made a recessive trait likely to surface and easy to fix.
So do not say mauritiana is the ancestor of laurina, and do not say laurina got its low caffeine from mauritiana. The published record points the other way, and the two plants are not easy partners in a cross in any case.
Where it grows and what the plant is like
This wild coffee grows nothing like farmed coffee. Mauritiana is a forest understorey plant, not a plantation plant. Reunion sources describe it as a shade-demanding species of humid forest, and it is used in ecological restoration plantings on the island for exactly that reason. It occurs not as stands but as scattered small patches of individuals distributed through the rainforest, which is a very different spatial pattern from a coffee farm and part of why nobody has ever harvested it at volume.
A published survey of Reunion populations, which sampled hundreds of individuals across dozens of locations, found the species across a wide altitudinal band, roughly 270 to 1,500 metres, spanning a considerable spread of mean temperature and a very wide rainfall gradient from moderately wet to some of the wettest terrain on the island. That study also found fine-scale genetic structure: populations diverged along both geographic distance and climatic gradients, with rainfall differences the strongest environmental signal, plausibly because they push populations into flowering at different times.
The plant itself reads as recognisably a coffee. Descriptions from Reunion botanical sources give a shrub or small tree that can reach around seven metres, with simple opposite leaves that are leathery and strongly reticulated, carrying domatia in the vein axils. The flowers are small, white and fragrant, borne in clusters in the leaf axils, and Reunion sources put the fruiting period across roughly the middle and second half of the year rather than in one short window. The fruit is a drupe like any coffee cherry, with its ripe colour reported variously as brownish-yellow through to purple, a good example of a detail where sources disagree and the honest answer is that accounts vary.
What is actually known about how it tastes
Very little of what is written about mauritiana comes from cupping panels. What exists is a long, consistent chain of descriptions rather than measurements, and the descriptions agree: the beverage made from mauritiana seed is sharp and bitter, and markedly more bitter than cultivated coffee.
That verdict is not new. Histories of coffee on Bourbon commonly date the formal noticing of the wild forest coffee to 1711, when an officer reported wild coffee trees in fruit and samples were sent to Paris for evaluation. Interest did not last. Within roughly a decade the island's plantings had swung decisively to arabica seed brought from the Red Sea port of Mokha, and the reasons given in historical accounts include both quality complaints and the wild tree's low, irregular yield. The species itself was not formally described until decades later, by Lamarck, and sources give the date as either 1783 or 1785, which is a small but fair illustration of how loose the record on this plant is.
The chemistry offers a plausible mechanism without pinning it down. Caffeine-free Madagascan coffees are known to accumulate an intensely bitter diterpene glycoside in the seed, mascaroside, and the general pattern in this island group is that the caffeine is missing while other bitter principles are not. Whether mauritiana's specific bitterness comes from that class of compound, from its load of phenolics and other alkaloids, or from something else has not been settled in anything you could call accessible literature. Research on the species has concentrated on its flavonoids, chlorogenic acids, mangiferin and trigonelline as compounds of pharmaceutical and cosmetic interest, rather than on building a flavour profile for a cup nobody is selling.
Treat any confident tasting note for mauritiana coffee with suspicion. There is no supply chain, no roast standard and no shared reference sample behind it.
Caffeine: low, but not a specification
Mauritiana is routinely listed among the naturally caffeine-free coffees, and that is close to right without being exactly right. The Mascarocoffea grouping owes much of its popular fame to the apparent absence of caffeine in these island seeds, and most references describe mauritiana seed as free of it or nearly so. Later analytical work complicated that picture: several species in the group turned out to hold trace amounts rather than none at all. Different sources will tell you "caffeine-free" and "very low in caffeine" with equal confidence, and no figure quoted for this species should be read as a specification, because the sampling behind published values is thin and wild populations vary.
The second honest conclusion is that the low caffeine here is not a route to a decaf product. Attempts to move the trait out of caffeine-free island coffees and into cultivated arabica and robusta ran into strong crossing barriers, with hybrids showing abnormal meiosis, poor pollen and effective sterility. That is a large part of why the idea has produced papers rather than a crop.
Why nobody grows it, honestly
The case against mauritiana as a crop is not one problem. It is several, and they compound:
- The cup. Bitterness that people have been complaining about since the eighteenth century is not a marketing problem to be solved with better processing.
- The architecture. A shade-demanding understorey tree that reaches seven metres and grows in scattered patches is not built for rows, pruning cycles and picking rounds.
- The yield. Early accounts describe a low-yielding tree carrying occasional fruit rather than the heavy, concentrated crop a picker needs to make a pass worthwhile.
- The absence of selection. Arabica has had three centuries of deliberate improvement. Mauritiana has had none: no yield selection, no uniformity, no processing know-how, no agronomic package at all.
- The genetics. The one trait most people want from it cannot easily be bred into arabica, because the hybrids do not work.
- The conservation position. An endemic forest tree confined to two islands, whose published conservation listings range from Vulnerable to Least Concern, is a poor candidate for wild harvest at any meaningful scale whichever listing you take.
Where the species does have a live human use, it is the leaves rather than the seed. Cafe marron is part of Reunion's herbal-infusion tradition, used locally for diuretic, anti-inflammatory and eye-lotion purposes, and it is registered in the French pharmacopoeia. That is a botanical and medicinal story rather than a coffee one, and it is worth keeping the two apart.
What it means for breeding and a warming coffee belt
The interesting argument for wild species like this one is not that any of them becomes the next crop. It is that a genus with well over a hundred described species holds adaptations, to heat, to drought, to shade, to disease and to an entirely different seed chemistry, that two cultivated species do not. Mauritiana has evolved across a steep tropical island with an enormous rainfall gradient, and the population work on Reunion suggests real local adaptation across that gradient. As a source of insight into how Coffea adapts, that is genuinely valuable.
As a source of genes for arabica, the honest position is much more cautious. The crossing barriers are documented and severe. Nobody should read "wild low-caffeine coffee species" as "future decaf crop", or as a timeline to anything. The realistic contributions are the conservation of an endemic tree, a better understanding of how caffeine biosynthesis came to be lost more than once in this genus, and the chemistry of what these seeds make instead.
One last disambiguation: the other cafe marron
The name cafe marron is also carried, on the neighbouring island of Rodrigues, by Ramosmania rodriguesii, a plant that is not a coffee at all although it sits in the same botanical family. That is the famous one: long presumed extinct, reduced to a single surviving wild tree found by a schoolboy in 1980, and eventually coaxed into setting viable seed in cultivation at Kew. Those events belong to Ramosmania, not to Coffea mauritiana, and at least one botanical database appears to attach that rediscovery narrative to the coffee species. If you meet a dramatic near-extinction story about cafe marron, check which plant it is about first.
The bottom line
Mauritiana coffee is a wild Coffea species endemic to Reunion and Mauritius, growing in shaded upland forest, carrying little or no caffeine and a reputation for severe bitterness that has survived three hundred years of people occasionally trying it. It is not Bourbon, it is not Bourbon pointu, it is not the parent of laurina, and calling it a variety gets the biology wrong at the first word. The record on it is genuinely thin in places, with ripe fruit colour, caffeine trace levels, altitude limits, conservation listing and flavour all carrying real uncertainty, and the most accurate thing to say about a plant like this is often that the documentation is sparse. That is more useful than a confident number nobody can source.