P.C. van Welzen

A TAXONOMIC RevIsION Of MAllOTus seCTION PhIlIPPINeNses (fORMeR seCTION ROTTleRA - euPhORbIACeAe) IN MAlesIA AND ThAIlAND

SUMMARY A revision of Mallotus section Philippinenses (former section Rottlera) in Malesia and Thailand is given. Descriptions, distribution maps, habit drawings, and a key to the species are provided. The diagnostic characters for the section are briefly discussed. Five species ( M. kongkandae, M. leptostachyus, M. pallidus, M. philippensis, and M. repandus) are recognised. Mallotus chromocarpus is excluded from the section because it has more shared characters with the monospecific genus Octospermum, like the presence of indehiscent fruits, absence of stipules, marginal extrafloral nectaries on the upper side of the leaf blade, broad connectives (shaped umbrella-like), and its occurrence in New Guinea, and is therefore probably closely related to it.

Re-shaping Mallotus [Part 2]: inclusionof Neotrewia, Octospermum and Trewia in Mallotus s.s. (Euphorbiaceaes.s.)

A recent molecular phylogenetic study of Mallotus and related genera showed that three small Asiatic genera are clearly part of a strongly supported main Mallotus clade (Mallotus s.s. clade), rendering the genus paraphyletic. In this paper these genera, Neotrewia, Octospermum and Trewia, are merged with Mallotus. The monotypic Neotrewia and Octospermum were originally described within Mallotus and are now transferred back to it. Trewia was never included in Mallotus; it has two distinct species, for which new combinations within Mallotus are made. A full taxonomic treatment with descriptions, distribution maps and drawings is given for the species transferred, and a new generic description for Mallotus is provided. The morphology of the newly transferred species in comparison to Mallotus in general and to related species in particular is discussed.

Patterns in species richness and composition of plant families in the Malay Archipelago.

Distribution patterns or the recognition of phytogeographical areas is usually based on the presence and absence of species. The taxa on which the analyses are based remain virtually anonymous. Here we want to determine which Malesian plant families (within the sample) are responsible for species richness and composition patterns. The other aim is to determine whether the different islands groups in Southeast Asia can be grouped into separate phytogeographical areas. A Principal Coordinates Analysis (PCO) showed the presence of three phytogeographical areas within Malesia: The Sunda Shelf (Malay Peninsula, Sumatra, Borneo) in the west, the Sahul Shelf (New Guinea) in the east, and all remaining central areas forming Wallacea. The latter can be divided into two parts (Java and the Lesser Sunda Islands versus the Philippines, Sulawesi and the Moluccas). Only twenty plant families (out of 164 sampled) account for most of the biodiversity on the island groups, both in total and endemic species numbers. These twenty families show a limited number of species richness patterns that are significantly associated with one or several of the detected phytogeographical areas. Only a few plant families were equally common throughout the whole Malesian region. Conservation efforts in Malesia should take this spatial distribution pattern into account in order to maximise preservation of both species diversity and complementarity.

Re-shaping Mallotus [Part 1]: Expanded circumscription and revision of the genus Cordemoya (Euphorbiaceae)

A recent phylogenetic study based on DNA sequence data detected a well-supported clade of a number of Mallotus species together with the genus Cordemoya. This clade is distinct from the large Mallotus s.s. clade. In this paper, Cordemoya (formerly monotypic with C. integrifolia from the Mascarene Islands) is expanded with sixteen additional species previously assigned to Mallotus. Taxa transferred to Cordemoya are: Mallotus sections Hancea and Oliganthae from Asia and M. baillonianus, M. capuronii, and M. spinulosus from Madagascar. The genus Cordemoya can be distinguished from Mallotus s.s. by the presence of pollen with areolate ornamentation with scabrae (perforate/microreticulate ornamentation with scabrae in the sample of Mallotus s.s. studied up to now) and of capitate glandular hairs with multicellular stalks and sessile peltate-stellate hairs with a central cell (spherical to disc-shaped multicellular glandular hairs in Mallotus). In the new circumscription of Cordemoya two subgenera are recognized: Cordemoya from Madagascar and Mascarenes and Diplochlamys from Asia. The latter is divided into two sections: Diplochlamys (former sect. Hancea), and Oliganthae. A taxonomic revision of part of these taxa is provided (excl. section Diplochlamys); descriptions, distribution maps, habit drawings and a key are included.

A taxonomic revision of Mallotus section Mallotus (Euphorbiaceae) in Malesia

A revision of Mallotus section Mallotus in Malesia is given. Descriptions, distribution maps, habit drawings and a key to all species are provided. The diagnostic characters for the section are briefly discussed. Four species (M. barbatus, M. macrostachyus, M. mollissimus, M. paniculatus) and one variety (M. paniculatus var. formosanus) are recognised.

Themorphological range in Mallotus (Euphorbiaceae) and a taxonomic revision ofits section Rottleropsis (including Axenfeldia) in Malesia, Thailand and Africa .

The range of diagnostic morphological features in the whole genus Mallotus is reviewed as background to the taxonomic treatment of section Rottleropsis s.l. Special emphasis is given to the indumentum, habit, stipules, leaves, extrafloral nectaries, domatia, inflorescences, flowers, pollen and fruits. Notes on the geographical distribution, ecology, pollinators, fruit and seed dispersal, and uses of the genus are also presented. The section Axenfeldia is reduced to sect. Rottleropsis on account of the absence of suitable morphological characters to distinguish them. A taxonomic revision of 38 species of sect. Rottleropsis s.l. from Malesia, Thailand and Africa is presented, together with regional and synoptical identification keys, distribution maps and illustrations. Four new species are described: Mallotus connatus, M. longinervis, M. minimifructus and M. mirus. Several non-Malesian species not included in this revision are briefly discussed. This paper concludes a series of taxonomic revisions of the genus Mallotus in Malesia and Thailand.

REVISION OF THE MALESIAN AND THAI SPECIES OF SAUROPUS (EUPHORBIACEAE: PHYLLANTHOIDEAE)

Fourteen species of Sauropus are recognised for Malesia, 21 for Thailand. Two species are described as new, S. asymmetricus of Sumatra and S. shawii of Borneo. Many new synonyms, especially for S. androgynus and S. rhamnoides, are provided. The latter two species have a much wider distribution than described before and both are difficult to separate from each other. A phylogeny based on morphological and palynological data proved futile, but showed that Sauropus together with Breynia and Glochidion are embedded in the paraphyletic Phyllanthus. Most species which formerly belonged to Synostemon and are now included in Sauropus are probably, with the exception of S. bacciformis, related to Breynia and Glochidion. Because of the poor phylogenetic results the circumscription of Sauropus is not changed (Synostemon still included), and an infrageneric classification is not provided.

Resurrection ofHancea and lectotypification of Adisca (Euphorbiaceae)

Based on phylogenetic studies with DNA sequence data, the formerly monotypic genus Cordemoya was recently expanded with 16 additional species previously assigned to Mallotus. However, the earliest legitimate generic name available is Hancea, and, therefore, Cordemoya is here reduced to Hancea (20 new combinations are proposed). Subsequently, the subgenus and section Diplochlamys from Asia are renamed to Hancea. Additionally, the genus Adisca is lectotypified with Adisca floribundus (= Mallotus floribundus).

THE MALLOTUS WRAYI COMPLEX (EUPHORBIACEAE)

The Mallotus wrayi King ex Hook.f. complex on the Sunda Shelf of the Malay Archipelago (Malay Peninsula, Sumatra, Java, Borneo) appeared to comprise four species instead of a single, very heterogeneous one. Two synonyms (M. caudatus Merr. and M. lancifolius Hook.f.) are resurrected and a new species, M. spinifructus, is described. Important characters can be found in the density of the hairs (glandular scale-like, simple or stellate), type of stellately bundled hairs, lengths of inflorescences, bracts, and bracts of the terminal bud, and in the stigma width and hairiness.

Phylogenetic reconstruction prompts taxonomic changes in Sauropus, Synostemon and Breynia (Phyllanthaceae tribe Phyllantheae)

Previous molecular phylogenetic studies indicated expansion of Breynia with inclusion of Sauropus s.str. (excluding Synostemon). The present study adds qualitative and quantitative morphological characters to molecular data to find more resolution and/or higher support for the subgroups within Breynia s.lat. However, the results show that combined molecular and morphological characters provide limited synergy. Morphology confirms and makes the infrageneric groups recognisable within Breynia s.lat. The status of the Sauropus androgynus complex is discussed. Nomenclatural changes of Sauropus species to Breynia are formalised. The genus Synostemon is reinstated.