A biographic summary of the research of Dr Graham Charles George Argent (born 15 May 1941, died 24 April 2019) is presented, summarising his research career. Expedition information, including dates, collection number series and the names of collaborators, is given, as is a list of his publications, annotated with taxonomic decisions and the names of new species described within them.

The species of the tree genus Pterospermum Schreb. (Malvaceae: Dombeyoideae) in Malesia are revised. Twenty-six species of Pterospermum are recognised, six of which are new (P. aureum S.K.Ganesan, P. borneense S.K.Ganesan, P. glabrum S.K.Ganesan, P. havilandii S.K.Ganesan, P. merrillianum S.K.Ganesan and P. zollingerianum S.K.Ganesan) and one (P. grewiifolium Pierre) that is a new distributional record for Malesia. Identification keys are provided. All names are typified, and detailed descriptions of all species recognised are provided. Information on habitat, uses and conservation status is given for all species.

Globba sect. Nudae subsect. Mediocalcaratae (K.Schum.) K.J.Williams is revised. Nineteen species are recognised. Eight names are lectotypified, three names are newly placed in synonymy, and two names are neotypified. A key to the species and descriptions are provided. Nine new species are described and illustrated: Globba argyrocycnos Sangvir. & M.F.Newman, G. cataractarum Sangvir. & M.F.Newman, G. chrysochila Sangvir. & M.F.Newman, G. decora Sangvir. & M.F.Newman, G. lilacina Sangvir. & M.F.Newman, G. newmanii Sangvir., G. nitens Sangvir. & M.F.Newman, G. pycnostachys Sangvir. & M.F.Newman and G. pyrrhopoikila Sangvir. & M.F.Newman. Six names based on five types from Thailand and the Philippines remain doubtful. Andromonoecy in this subsection is defined. Provisional IUCN conservation assessments of all species are supplied.

Odontostemma balfouriana (W.W.Sm.) Satish Chandra & D.S.Rawat is recorded here as a new record for the flora of India. Surprisingly, the species (previously known as Arenaria balfouriana W.W.Sm.) was erroneously considered to be a synonym of Stellaria depauperata Edgew. After examining protologues, fresh specimens and herbarium specimens housed in BSD, CAL and DD, the authors have resolved this taxonomic confusion and provided a new combination and lectotype for Arenaria balfouriana. Additionally, Stellaria depauperata, illegitimately combined under Arenaria, is resurrected and recognised as a distinct species.

The focus of community ecology has shifted from the description of taxonomic composition towards an understanding of community assembly based on species’ ‘functional traits’. The functional trait approach is well developed for vascular plants, utilising variability of continuous phenotypic characters that affect ecological fitness, such as specific leaf area, tissue nitrogen concentration or seed mass, to explain community structure. In contrast, community assembly studies for poikilohydric cryptogamic plants and fungi, such as lichens, remain focused on broad categorical traits such as growth form difference: fruticose, foliose or crustose. This study examined intra- and interspecific variability for two highly promising continuous phenotypic measurements that affect lichen physiology and ecological fitness: water-holding capacity (WHC) and specific thallus mass (STM). Values for WHC and STM were compared within and among species, and within and among key macrolichen growth forms (fruticose and green-algal and cyanolichen foliose species), asking whether these widely used categories adequately differentiate the continuous variables (WHC and STM). We show large intra- and interspecific variability that does not map satisfactorily onto growth form categories, and on this basis provide recommendations and caveats in the future use of lichen functional traits.

The species of Jasminum Tourn. ex L. (Oleaceae) in Peninsular Malaysia are revised. Eighteen species are recognised, of which eight are endemic. Five of these species have been recorded from Singapore. A key to species is provided, all names are typified, and all species are described. Conservation assessments are given for all species in Peninsular Malaysia. One species is Extinct in Peninsular Malaysia, eleven are Endangered and one is Data Deficient. Jasminum shahii Kiew is described as a new species. In Singapore, two species are certainly Extinct.

Two new species, Begonia bracteolata and Begonia keralensis, are described from the Western Ghats of India. They are placed in the newly created Begonia sect. Flocciferae, along with B. albo-coccinea Hook. and B. floccifera Bedd. Lectotypes are designated for three names within this section. Colour photoplates, illustrations and an identification key to Begonia sect. Flocciferae are also provided.

Cerrado sensu stricto (a physiognomy of the Cerrado domain, the Brazilian savanna) is subject to the annual occurrence of fire. Data on the epiphytic community in this physiognomy is scarce, as is evaluation of the influence of fire on its structure and composition. The aim of this study was to describe the structure of the vascular epiphyte community and its relationships with phorophytes in the Cerrado domain, Southeast Region of Brazil, after the passage of fire. We found the greatest abundance of epiphytes in the upper strata (65% of the individuals occurring above 3 m in height) and the dominance of three generalist species (Tillandsia streptocarpa, T. recurvata and Epiphyllum phyllanthus), suggesting that fire has an influence on the structure and composition of the epiphytic community.

Recent botanical explorations in the province of Palawan, Philippines, have resulted in the discovery of two new ginger species, namely Boesenbergia eburnea Docot and Boesenbergia leonardocoi Funak. & Docot, which are described and illustrated here, including information on their distribution, habitat, phenology, ecology and conservation status. Additionally, a key to Boesenbergia species in the Philippines is provided.

Curcuma cinnabarina and C. eburnea (Curcuma subg. Ecomatae, Zingiberaceae), two new species from Thailand, are described and illustrated here. They are compared with the morphologically closest species Curcuma rubrobracteata and C. pierreana, respectively. Detailed descriptions, colour plates, and information on their distribution, ecology, phenology and uses are also provided. Preliminary IUCN conservation assessments of these species are proposed.

A striking new species of Diastema, D. fimbratiloba, is described from Ucayali Region, along the eastern Andean slopes in central Peru. The new species has a fimbriate lower corolla lobe, a feature not previously documented in the genus. We also provide a general comparison of the newly described species and morphologically related species in the context of the taxonomy and phylogeny of the poorly known genus Diastema.

Begonia keralensis Pradeep, Sinj. Thomas & Britto and Begonia bachulkarii Aitawade, Kattuk. & S.R.Yadav were independently described recently from Nelliyampathy in Kerala, India, within two weeks of each other. The names are based on different types but represent the same taxon. Because Begonia bachulkarii is the earliest published name, Begonia keralensis is reduced to synonymy.

Epiphytes are an important component of the diversity of tropical forests, and they also have several ecological functions. Vegetation heterogeneity is one of the features responsible for the high biodiversity of the Atlantic Forest, especially in the domain’s seasonal semideciduous forest (SSF). This biodiversity presents as high endemism and species richness. Owing to the seasonal nature of SSF, organisms that require high humidity (e.g. epiphytes) would be expected to show low species richness in these forests. The aims of this study were to conduct a survey of the vascular epiphytes in remnants of montane SSF in the Serra do Ibitipoca, Brazil, and to evaluate the importance of habitat heterogeneity for the richness and composition of species in these areas. We also evaluated whether the intrinsic characteristics of the SSF phytophysiognomy and fragmentation could result in low species richness and a high number of accidental epiphyte species. The study was conducted in the course of 18 expeditions undertaken between September 2013 and December 2016, covering five fragments of montane SSF (totalling 23.6 ha). We recorded 96 species (only one of which is an accidental epiphyte), distributed across 41 genera and 10 families. This is the highest epiphytic species richness recorded in Brazilian SSF to date. The results refuted the initial hypothesis and reinforce the importance to the epiphytic community of conservation of fragments with different structures.

We describe two new species of Heteropterys (Malpighiaceae) endemic to the Atlantic Forest of Espírito Santo State, Brazil. Heteropterys eucalyptifolia and H. follianum belong to the Aptychia informal group, due to their petioles with a pair of glands at the base, sessile pedicels, petals exposed in the enlarging bud, and strongly heteromorphic filaments. Morphological descriptions, illustrations, a distribution map and information on the conservation status of the species are provided.

Memecylon nervosum Vadhyar, J.H.F.Benj. & Sujana, a new species of Melastomataceae from the Kanyakumari Wildlife Sanctuary, Western Ghats, India, is described and illustrated. It is compared with the closely allied Memecylon heyneanum Benth. and Memecylon jambosioides Wight.

The new species Begonia maguniana H.P.Wilson from New Guinea is described. It is endemic to the Central Range of New Guinea at altitudes of c.1700–2300 m and belongs to the IUCN category Least Concern.

Sixty new or updated records of plants species are reported from the Sultanate of Oman, as a result of fieldwork and research undertaken. Five taxa represent new records for Arabia, twenty-seven taxa are new records for Oman, and twenty-eight records represent an extended distribution within Oman. Some previously doubtful records are confirmed. Brief comments are given on the phytogeography, taxonomy and ecology of the taxa. Most new records have been collected in mountainous areas, either in southern Oman or in northern Oman, mainly in areas that previously were botanically poorly known.

A new species of Eriocaulon, E. vamanae, is described from the southern Western Ghats of Kerala, India. It resembles Eriocaulon nepalense var. luzulifolium (Mart.) Praj. & J.Parn. but differs in the shape of its involucral bracts and receptacle, the fusion of the sepals in male flowers, the shape and indumentum of the sepals in female flowers, the size and indumentum of the petals in female flowers, and the seed coat appendages. Eriocaulon vamanae is so far known only from the type locality, Meesapulimala in Idukki District, Kerala, and is assessed as ‘Critically Endangered’ according to the IUCN’s Red List Categories and Criteria.

A taxonomic revision of Begonia veitchii Hook.f. is presented. Two taxa are newly recognised as synonyms of Begonia veitchii: B. baumannii Lemoine and B. clarkei Hook.f. Addditionally, two infraspecific taxa are newly described and illustrated: Begonia veitchii var. machupicchuensis Tebbitt, which is endemic to the Cusco Department of Peru, and B. veitchii var. lanatifolia Tebbitt, which is endemic to Chuquisaca Department, Bolivia. Begonia veitchii, as well as four taxa recognised as synonyms of B. veitchii – B. baumannii, B. rosaeflora Hook.f., B. coriacea A.DC. and B. clarkei – are lectotypified. A key, descriptions, distribution map and illustrations are provided for all the recognised infraspecific taxa of Begonia veitchii.

Six new species of Vaccinium, identified as new to science by the late George Argent while compiling a revision of Vaccinium sect. Orianthe for New Guinea, are described and illustrations provided.