Species radiations, despite immense phenotypic variation, can be difficult to resolve phylogenetically when genetic change poorly matches the rapidity of diversification. Genomic potential furnished by palaeopolyploidy, and relative roles for adaptation, random drift and hybridisation in the apportionment of genetic variation, remain poorly understood factors. Here, we study these aspects in a model radiation, Syzygium, the most species-rich tree genus worldwide. Genomes of 182 distinct species and 58 unidentified taxa are compared against a chromosome-level reference genome of the sea apple, Syzygium grande. We show that while Syzygium shares an ancient genome doubling event with other Myrtales, little evidence exists for recent polyploidy events. Phylogenomics confirms that Syzygium originated in Australia-New Guinea and diversified in multiple migrations, eastward to the Pacific and westward to India and Africa, in bursts of speciation visible as poorly resolved branches on phylogenies. Furthermore, some sublineages demonstrate genomic clines that recapitulate cladogenetic events, suggesting that stepwise geographic speciation, a neutral process, has been important in Syzygium diversification.

Ramentae are hair-like structures found on the perigone tube and diaphragm in species of Rafflesia (Rafflesiaceae). Although ramenta morphology provides an important taxonomic character, a consistent terminology has not been used in species descriptions. As such, morphological comparisons among species as well as among populations within a species are difficult. We used a variety of resources to document the morphology including the location and density of ramenta among 18 species of Rafflesia and between populations and/or sexes of two species. We identified five types of ramenta: tuberculate, filiform, swollen apex, toadstool, and fence-like and recognized several variations within each type. Ramenta types characterize four species complexes: R. patma (tuberculate), R. arnoldii (filiform), R. pricei (mostly swollen apex), and R. hasseltii (mostly toadstool). Our classification of ramenta offers a tool for using consistent terminology to re-evaluate previously described species and to define new species of Rafflesia.

MAHYUNI, R., KUSUMA,Y. W. C., WIHERMANTO & VELDKAMP, J. F. 2015. Notes on Rafflesia (Rafflesiaceae) in Sumatra with a new record Rafflesia gadutensis Meijer. Reinwardtia 14(2): 317 - 322. Pulau Mursala is a small island west of the Sibolga, Tapanuli Tengah District, North Sumatra, Indonesia. The occurrence of the genus Rafflesia (Rafflesiaceae) there has never been reported before. However, during a visit in April 2013 three populations are located close together with more than twenty buds and some rotting blooming flowers, Tetrastigma sp. was detected. Field observations could be made and material was collected for comparison with that in the Herbarium Bogoriense (BO). It was concluded that they are R.gadutensis Meijer, which is known from Padang, Ulu Gadut. Notes on its morphology are given. The distribution of species is discussed.

Abstract. Mahyuni R, Chikmawati T, Ariyanti NS. 2019. Short Communication: Two new species and new record of  Psydrax Gaertn. (Rubiaceae: Vanguerieae) in Borneo. Biodiversitas 20: 2011-2015. Psydrax sabahensis Mahyuni and P. wongii Mahyuni are two new species endemic to Borneo proposed in this present study with descriptions, illustrations and map of distribution provided. Psydrax sabahensis has blades ovate to elliptic, with angle 60º to the midrib, tertiary venation conspicuous on both side, petiole length 10-13 mm long, inflorescence sub-umbellate and pedicels 23-27 mm long. Psydrax wongii has blade elliptic, with angle 45º to midrib, apex acuminate to caudate, secondary veins 3-4 pairs, tertiary venation inconspicuous on upper side and slightly wrinkled on lower surface. The presence of P. maingayi (Hook.f.) Bridson in Borneo, previously thought to be a Malay Peninsula endemic species, is also confirmed as a new record.

The mycoheterotrophic genus Gymnosiphon Blume is recorded for Australia for the first time after the recent discovery of plants at Mossman Gorge, Queensland. On the basis of examination of living plants in the field as well as materials preserved in spirit, the Mossman Gorge Gymnosiphon taxon is a novelty closely related to Gymnosiphon affinis J.J.Sm., which is known only from New Guinea. The new species is here described as Gymnosiphon queenslandicus B.Gray & Y.W.Low based on floral characteristics important for species distinction in the genus.