Geography and distribution
Restricted to western Madagascar, Mahajanga Province, Soalala District, in the Réserve Naturelle Intégrale Namoroka (RN 8).
Coffea pterocarpa is one of the most bizarre-looking species of coffee, owing to its yellow-green or yellow, conspicuously winged fruits. It is possible that the wings may make the fruits more visible to animals, such as lemurs and birds, which could act as dispersal agents.
Another possibility is that the fruits are adapted to water-dispersal, as the fruits float very well, unlike most coffee species, which usually sink when placed in water. As in many areas of western Madagascar, Namoroka receives a large amount of rainfall during the wet season, which produces many ephemeral water courses.
Overview: A small, single-stemmed but well-branched tree, about 7 m high. The diameter of the main stem at breast height is 6 to 6.5 cm.
Leaves: Borne in opposite pairs on the stem. Each leaf pair has a stipule (scale-like appendage) between the petioles (leaf-stalks). The leaf blades are normally oval to egg-shaped in outline, 5.5 to 7 cm long by 1.8 to 3.8 cm wide, with seven to nine pairs of secondary veins. The under-surface of the leaves is slightly hairy on the midrib and veins.
Flowers: The appearance of the flowers is currently unknown but they are likely to be long-tubular and white.
Fruits: More or less egg-shaped and 2.6 to 3.6 cm long by 2.2 to 3.8 cm wide. The fruits are distinctly winged, with 16 to 20 wings on each fruit, each wing being 0.9 to 1.2 cm high. The immature fruits are yellow-green, and they are thought to be yellow at maturity. Each fruit contains two seeds (‘coffee beans’).
Threats and conservation
Coffea pterocarpa is known only from the small protected area of Namoroka, in western Madagascar. During its discovery in 2000 fewer than ten plants were found, and it has only been collected three times. It is possible that it may be found elsewhere in Namoroka, although the total area of the reserve is only 220 square kilometres, with suitable habitat considerably less. Further field studies are required.
Remarkable new coffee species
Botanical exploration in Madagascar has unearthed six new species of coffee belonging to the baracoffea alliance, a morphologically unique group of nine species restricted to the seasonally dry forests of western Madagascar.
The new species are some of the most remarkable in the genus, looking totally different from most coffees. Coffea labatii and C. pterocarpa are notable for having distinctly winged fruits and C. ambongensis and C. boinensis have the largest seeds of any coffee species, their ‘coffee beans’ being more than twice the size of those of C. arabica.
Coffea pterocarpa and C. namorokensis were found in 2000, after an expedition to the isolated Namoroka Reserve, although recently an old collection (1952) of C. pterocarpa was discovered in a herbarium in Madagascar.
Coffea ambongenis was rediscovered in 1999 after not being seen by scientists since 1852. To our knowledge, none of the new species has been tried as a beverage but as with all other coffee species the fruit contains the characteristic coffee bean. These six new species bring the total number of coffee species to 103.
Kew plant hunters discover species in Madagascar
In the wet season of 2000 two botanists from Kew and one counterpart from Antananarivo in Madagascar set out on a bold mission to collect plants from the little-known and poorly collected reserve of Namoroka (Réserve Naturelle Intégrale Namoroka), in a remote part of western Madagascar. This reserve had not been visited for serious botanical collecting since 1952.
Aaron Davis and Franck Rakotonasolo plant-hunting in Madagascar.
It is possible to reach Namoroka by light aircraft and even by four-wheel drive, but only in the dry season when a visit to this deciduous forest would be of little value to the botanist, with little in flower, fruit, or leaf. Reaching the reserve took three days, two days walking (from sunrise to sunset) and one day in-between, the team sheltering in their tents from a cyclone.
Fortunately, all equipment and luggage was carried on a zebu cart. On the third day, after the cyclone had passed, the team reached Namoroka, to see giant baobabs in several feet of water amid large vertical and horizontal slabs of limestone, some of which were razor-sharp and very difficult to walk though.
They could only spend one week at Namoroka, as the food supplies had been damaged by water, as a result of the numerous stream crossings and persistent rain. However, during the short stay they were able to re-collect many rare and interesting plants, and several new species, including a new species of yam (Dioscorea namorokensis), and the species of coffee Coffea namorokensis (new) and C. pterocarpa (rediscovered).