INDIAN OCEAN MAPOURIA SPECIES TRANSFERRED TO PSYCHOTRIA ( RUBIACEAE – PSYCHOTRIEAE )

Mapouria Aubl. is a synonym of Psychotria L. In Madagascar and the Comoros there are 67 species of Mapouria that fall within the circumscription of Psychotria and correspondingly 64 species (67 taxa) require transfer to Psychotria. Thirty-seven new combinations and 30 new names are proposed; five lectotypes are designated.

In his summary on the identity of the genera Mapouria and Grumilea Gaertn., Bremekamp (1961: 319) stated that Mapouria should be applied to members of the tribe Psychotrieae that possess deciduous stipules, heterostylous flowers, pyrenes lacking a longitudinal intrusion on the commissural (ventral/adaxial) surface, and endosperm that is either ruminate on the adaxial surface only or extends over the whole surface.Bremekamp asserted that Mapouria, which was formerly used only for New World Psychotrieae, should be used for species that were previously included in Grumilea, and that Mapouria need not be given up in favour of Psychotria.On this basis, Bremekamp (1963) enumerated 67 species of Mapouria from Madagascar and the Comoros, mostly described as new species but some were transferred from Psychotria.
Following Bremekamp (1963), Petit (1964) wrote his revision of continental African Psychotria.In this work Petit clearly and succinctly stated that there are few, if any, differences between Mapouria and Psychotria, and specifically that the characterization for Mapouria as given by Bremekamp (1963), and as outlined above, included many of the African species.Petit (1964: 24) averred that Mapouria should not be upheld.This view was supported by Steyermark (1972: 444-446).Some years later, Hamilton (1989) formally placed Mapouria into the synonymy of Psychotria, a decision that has been widely accepted (Taylor, 1996;Andersson, 2002).Andersson (2002) sampled two species of Madagascan Mapouria (M.ankafinensis K. Schum.and M. macrochlamys Bremek.) in his assessment of the Psychotria complex (Psychotrieae), using data from the rps16 intron.Mapouria macrochlamys (Mapouria series VI) was placed in Psychotria s.s.clade III, with the neotropical type of Mapouria, and M. ankafinensis (Mapouria series III) was unresolved in Psychotria s.s.Despite the paucity of molecular information for Indian Ocean Mapouria, the data provided by Andersson (2002) is consistent with the placement of Mapouria as a synonym of Psychotria.
Nearly all species of Old World Mapouria have now been placed in Psychotria or other genera of Psychotrieae (see www.rbgkew.org.uk/wcsp/rubiaceae).Conspicuously, there remain 67 Indian Ocean species of Mapouria.After 1) careful review of the generic and species descriptions (Bremekamp, 1963); 2) examination of type specimens and/or other authentic material held at K and P (abbreviations after Holmgren et al., 1990); and 3) field study (by A. Davis), it is clear that these Mapouria species conform to characterization of Psychotria (Petit, 1964;Davis et al., 2001;Andersson, 2002).We therefore take the opportunity to transfer 67 species of Indian Ocean Mapouria to Psychotria.We have maintained the species delimitations made by Bremekamp (1963) for the 67 Mapouria species and believe that at the present time there is no need for species-level synonymy.Despite identifying numerous new collections of Madagascan Mapouria in the last ten years we have so far identified no potential synonyms.Indeed, it is likely that there are several new species that require formal description.Indian Ocean Mapouria mostly have terminal inflorescences and yellow corollas, a combination of characters that is also present in some species of Africa Psychotria, such as P. capensis (Eckl.)Vatke.However, there is also a group of species with axillary or near-axillary inflorescences, that have white, red or reddish corollas (Mapouria series I of Bremekamp, 1963).Axillary inflorescences are rare in Psychotria and the Psychotrieae (A.Davis, unpubl.data) but otherwise these species conform to African Psychotria (Petit, 1964).
In addition to the taxonomic treatment of Mapouria and Psychotria by Bremekamp (1963), he also revised four other Psychotrieae genera occurring in Madagascar and the Comoros, viz.Apomuria Bremek., Trigonopyren Bremek., Carinta W. Wight and Psathura Comm.ex A. Juss.Carinta is a synonym of Geophila D. Don, but the others are accepted names.Apomuria and Trigonopyren seem to fall within the delimitation of Psychotria, resembling some of the species from continental Africa in general morphology and pyrene structure.Psathura has a multilocular ovary, with 3-6 locules, but otherwise has the potential to be incorporated within Psychotria.Further work is required to ascertain the taxonomic placement of these three genera.

METHODS
Herbarium material was consulted at the Muséum National d'Histoire Naturelle, Paris (P), and the Royal Botanic Gardens, Kew (K).All specimens cited here have been seen by us, unless indicated otherwise (non vidi: n.v.).Some species were examined in the field in Madagascar, during eight field trips over a nine year period (1996-2004) by A. Davis (unpubl.data).Pyrenes were prepared by immersing fruits in boiling water for three to five minutes, depending on the size and thickness of the fruit.The mesocarp (and any other soft tissue) was removed using a blunt scalpel blade and blunt needle.The presence vs absence of preformed germination slits (PGSs) was assessed upon removal of the mesocarp.The endosperm was examined by cutting the pyrene in transverse section with a sharp scalpel.To test for an ethanol soluble pigment, a single seed, or one half of a seed, was placed into a test-tube and covered with 70% ethanol for c. 5 minutes, at room temperature.The resulting solution was held against a white piece of paper and the colour assessed.On completion of the test, the seeds were dried and returned to their respective herbarium sheets.Pyrene observations were made using a Leica MZ95 stereomicroscope.

PYRENE MORPHOLOGY
All species formerly included in Mapouria from Madagascar and the Comoros have the same basic pyrene structure, which is the same as most Africa Psychotria: the pyrenes lack preformed germination slits (PGSs; see Petit, 1964;Robbrecht, 1988Robbrecht, , 1989;;Davis et al., 2001;Piesschaert, 2001), the endosperm is ruminate and the testa has an ethanol (70%) soluble pigment (see Petit, 1964), which turns ethanol red (see Methods).According to Bremekamp (1963: 6, 8) the lack of a longitudinal intrusion on the inner (adaxial) face of each pyrene (as present in some Psychotria spp.) is a key feature of Mapouria.Indeed, the pyrenes of most species of Madagascan Mapouria examined by us are like this, but there are also many species of continental African Psychotria (Petit, 1964) and Asian Psychotria (A.Davis, pers.observ.)that lack a longitudinal intrusion on the inner face of each pyrene.

TRANSFER OF INDIAN OCEAN MAPOURIA TO PSYCHOTRIA
For the transfer of Indian Ocean Mapouria species given below we have retained the species in the same number order as Bremekamp (1963), and have kept the species within their respective informal series groups (Series I-VII).This will make it easier to use the identification keys provided by Bremekamp (1963) (Bremekamp, 1963: 68, 71-73; and as labelled on specimens).Bremekamp (1963: 68) did not place Baron 2969 and 3015 with either of the aforementioned species: on herbarium specimens he determined them as M. boenyana cf.
[sic].These specimens differ from P. reducta and P. parkeri in the presence of short hairs on the undersurface of the leaf (vs glabrous) and a more or less repand calyx rim (vs lobed), although there may be other differences.Further work may show that P. mesentericarpa is conspecific with P. parkeri, but for the time being we recognize them as distinct.We take the opportunity here of lectotypifying P. mesentericarpa with the specimen Baron 2969.