S.E.C. Sierra

Molecular phylogeny of Macaranga, Mallotus, and related genera (Euphorbiaceae s.s.): insights from plastid and nuclear DNA sequence data

Macaranga and Mallotus (Euphorbiaceae s.s.) are two closely related, large paleo(sub)tropical genera. To investigate the phylogenetic relationships between and within them and to determine the position of related genera belonging to the subtribe Rottlerinae, we sequenced one plastid (trnL-F) and three nuclear (ITS, ncpGS, phyC) markers for species representative of these genera. The analyses demonstrated the monophyly of Macaranga and the paraphyly of Mallotus and revealed three highly supported main clades. The genera Cordemoya and Deuteromallotus and the Mallotus sections Hancea and Oliganthae form a basal Cordemoya s.l. clade. The two other clades, the Macaranga clade and the Mallotus s.s. clade (the latter with Coccoceras, Neotrewia, Octospermum, and Trewia), are sister groups. In the Macaranga clade, two basal lineages (comprising mostly sect. Pseudorottlera) and a crown group with three geographically homogenous main clades were identified. The phylogeny of the Mallotus s.s. clade is less clear because of internal conflict in all four data sets. Many of the sections and informal infrageneric groups of Macaranga and Mallotus do not appear to be monophyletic. In both the Macaranga and Mallotus s.s. clades, the African and/or Madagascan taxa are nested in Asian clades, suggesting migrations or dispersals from Asia to Africa and Madagascar.

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.

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.

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.

How to tackle revisions of large genera: lessons from Macaranga and Mallotus (Euphorbiaceae)

Two approaches to revise large genera are discussed. The first approach can be done by a single person, who revises the genus area after area. The other approach is by a team that revises per infrageneric taxon (preferably a single person per infrageneric group). The two approaches have their positive and negative sides, but both give good results. One problem with both approaches is to keep an overview of a possible infrageneric classification. The latter problem can be tackled by performing phylogenetic analyses based on molecular markers (providing core phylogeny) in combination with morphological, palynological, and anatomical data (providing apomorphies for infrageneric taxa).

THE DISTINCTION OF FIVE MALLOTUS SPECIES FORMERLY IN SECTION HANCEA (EUPHORBIACEAE)

Mallotus concinnus Airy Shaw, M. havilandii Airy Shaw, M. insularum (Airy Shaw) Slik, and M. miquelianus (Scheff.) Boerl. are very similar in appearance, with opposite leaves of which one large and elliptic, and the other reduced and more or less obcordate. However, a detailed look revealed enough differences to regard them as distinct species.