Kanchana Pruesapan

Delimitation of Sauropus (Phyllanthaceae) Based on Plastid matK and Nuclear Ribosomal ITS DNA Sequence Data

BACKGROUND AND AIMS A recent molecular phylogenetic study showed that Sauropus is deeply embedded within Phyllanthus together with its allies, Breynia and Glochidion. As relationships within Sauropus are still problematic and the relationship with Breynia has long been doubted, more molecular data are needed to test/corroborate such a broad definition of Phyllanthus. This study aims to clarify the status and delimitation of Sauropus and establish its position within Phyllanthaceae. METHODS Plastid matK and nuclear ribosomal ITS DNA sequence data for Sauropus and its allies were used to construct phylogenetic trees using maximum parsimony and Bayesian methods. KEY RESULTS Within Phyllanthus, Sauropus can be split into the mainly south-east Asian Sauropus sensu stricto (s.s.) plus Breynia and the mainly Australian Sauropus (formerly Synostemon). Sauropus s.s. plus Breynia comprise two distinct clades; one is the combination of Sauropus sections Glochidioidei, Sauropus and Schizanthi and the other is the combination of Sauropus sections Cryptogynium and Hemisauropus and the monophyletic genus Breynia. CONCLUSIONS Molecular data indicate that Synostemon should be reinstated at the same level as Sauropus s.s. and that Sauropus s.s. should be united with Breynia under the latter, older name. The molecular data corroborate only two of the five infrageneric groups of Sauropus recognized on the basis of morphological data.

Phylogeny and proposed circumscription of Breynia, Sauropus and Synostemon (Phyllanthaceae), based on chloroplast and nuclear DNA sequences

Abstract. Previous estimates of phylogeny in the Phyllanthaceae, Phyllantheae, have been hampered by undersampling of species from morphologically distinctive groups and using too few gene regions. To increase the phylogenetic resolution, sequences of two nuclear (ITS1–5.8S–ITS2) and Phytochrome C (PHYC)) and two non-coding chloroplast (accD–psaI, trnS–trnG) DNA markers were analysed using maximum parsimony and Bayesian inference with expanded sampling in Breynia, Glochidion, Sauropus and Synostemon. Our results supported reinstatement of Synostemon, previously included in Sauropus s.str., to generic rank, and provided evidence towards its future infrageneric classification. The results also indicated expansion of Breynia to include Sauropus s.str.; this combined monophyletic group consists of two strongly supported clades. Finally, we showed monophyly for Glochidion, which is sister to Phyllanthus subg. Phyllanthodendron, both still remaining undersampled. Morphological features characteristic of Breynia, Sauropus and Synostemon are discussed, as well as the desirability of dividing Phyllanthus into smaller genera.

Pollen morphology of Trichosanthes (Cucurbitaceae)

The pollen morphology of 37 species of Trichosanthes was examined, using light microscopy, and scanning and transmission electron microscopy. On the basis of the diverse exine ornamentation it is possible to distinguish five pollen types. With aperture characters, two of them can be subdivided into subtypes. Two types can be characterised with ultrastructural features as well. It appeared that several of the types (alt. subtypes) correspond very well to existing macromorphological groupings. The most deviating type, including only the monotypic section Trichosanthes (T. cucumerina), shows verrucate ornamentation, a thick granular infratectum and a thin, indistinctly delimited nexine. It is similar to that of the Madagascan genus Tricyclandra.

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.

Pollen morphology of Zehneria s.l. (Cucurbitaceae)

In order to provide additional data for the proposed subdivision of the palaeotropical genus Zehneria (Cucurbitaceae, tribe Benincaseae, subtribe Cucumerinae) by De Wilde and Duyfjes (2006) into five genera (Indomelothria, Neoachmandra, Scopellaria, Urceodiscus and Zehneria s.s.) pollen was examined using light and scanning electron microscopy for 18 Zehneria species including representatives of each of the proposed subdivisions, plus one species of the neotropical genus Melothria to which Zehneria once belonged. The pollen of Indomelothria, Scopellaria and Urceodiscus are described for the first time. Indomelothria, Neoachmandra and Zehneria s.s. have the same pollen type (3‐colporate, microreticulate to reticulate), which cannot be distinguished from that of Melothria. Scopellaria deviates by its irregularly striate‐reticulate ornamentation and short colpi, and Urceodiscus by its striate‐reticulate ornamentation. This result supports separation of Scopellaria and Urceodiscus as separate genera, but neither supports or rejects the segregation of Indomelothria and Neoachmandra. The pollen type shared by Indomelothria, Neoachmandra and Zehneria s.s. fits very well in the Cucumerinae. However, the striate‐reticulate ornamentation of Scopellaria and Urceodiscus pollen is unknown within this subtribe, and leaves some doubt with respect to the (sub)tribal assignment of both Scopellaria and Urceodiscus. Based on pollen morphology alone, the African Neoachmandra(?) peneyana does not belong to the tribe Benincaseae. Within the Cucurbitaceae, the 6‐aperturate pollen type of Neoachmandra (?) peneyana occurs only in the exclusively neotropical tribe Sicyeae.

Molecular data consistently recover a ‘Queensland clade’ of Synostemon (Phyllanthaceae, Phyllantheae) with distinctive floral morphology

Abstract. Molecular analysis of the newly reinstated genus Synostemon F.Muell. (Phyllanthaceae, Phyllantheae), using ITS sequence data from the now densely sampled genus, confirmed that the previously recognised ‘Queensland clade’ consists of Synostemon albiflorus (F.Muell. ex Müll.Arg.) Airy Shaw, S. sphenophyllus Airy Shaw, Sauropus podenzanae (S.Moore) Airy Shaw and the undescribed Synostemon spinescens, sp. nov. ined., the latter being validated here as S. spinosus I.Telford & J.J.Bruhl. Morphological synapomorphies for the clade are as follows: linear, apiculate anthers that are connivent but only basally connate, and thickened, clavate, recurved stigmas. A new combination is provided under Synostemon for Sauropus podenzanae as Synostemon podenzanae (S.Moore) I.Telford & Pruesapan and Sauropus convallarioides J.T.Hunter & J.J.Bruhl is formally placed in synonymy under Synostemon sphenophyllus. Descriptions, distributional data and notes on ecology and conservation status are provided for these species. Phyllanthus albiflorus F.Muell. ex Müll.Arg., the basionym of Synostemon albiflorus, is lectotypified.

Morphological and molecular data show Synostemon trachyspermus (Phyllanthaceae, Phyllantheae) to be a heterogeneous species assemblage

Abstract. Synostemon trachyspermus (F.Muell.) I.Telford & Pruesapan (Phyllanthaceae, Phyllantheae) is shown, by morphological studies and phylogenetic analysis using nrITS DNA sequence data, to be a heterogeneous species assemblage of four species. Phyllanthus rhytidospermus F.Muell. ex Müll.Arg., with a new combination provided as Synostemon rhytidospermus (F.Muell. ex Müll.Arg.) I.Telford & Pruesapan, and Sauropus hubbardii Airy Shaw, with a new combination as Synostemon hubbardii (Airy Shaw) I.Telford & Pruesapan, are re-instated as species. Phyllanthus arnhemicus S.Moore is lectotypified and placed in synonomy under Synostemon lissocarpus (S.Moore) I.Telford & Pruesapan, which is the new combination provided for Phyllanthus lissocarpus S.Moore (syn. Sauropus lissocarpus (S.Moore) Airy Shaw). Synostemon umbrosus I.Telford & J.J.Bruhl, a rare endemic from the Kimberley, Western Australia, is named as new. The newly described S. hamersleyensis I.Telford & Naaykens, endemic to the Pilbara, Western Australia, and the north-eastern Queensland endemic Sauropus aphyllus J.T.Hunter & J.J.Bruhl are shown to be closely related; the new combination Synostemon aphyllus (J.T.Hunter & J.J.Bruhl) I.Telford & Pruesapan is provided for the latter. Sauropus sp. A of Flora of the Kimberley Region, previously included within S. trachyspermus sens.lat., shows a more distant relationship and is named as Synostemon judithae I.Telford & J.J.Bruhl. Notes on distribution, habitat, phenology, conservation status, photomicrographs of seeds and a key to identification of the species are provided.