Robert Douglas Stone

• PhD
• Research Associate at University of KwaZulu-Natal

We emphasise the urgent need to conserve the Ebo forest (Littoral Region, Cameroon), which holds 10 strict endemic plant species and 15 near endemics for a total of 25, a very high number far exceeding the threshold for its recent status as an Important Plant Area (IPA). We describe a further strict endemic species from the Ebo Forest, Memecylon eb...

The tribe Sonerileae in tropical Africa and Madagascar is a morphologically diverse lineage that consists of 239 species in 10 genera. In this study, we present the first in‐depth phylogenetic analysis of African Sonerileae to test monophyly of the currently recognised genera. Phylogenetic analyses were performed using sequence data from two nuclea...

The Melastomataceae, with some 5858 species, are among the 10 largest families of flowering plants. Melastomes are subcosmopolitan and mainly distributed in the tropics and subtropics, with a majority of the species in the Neotropics. The family consists of 173 genera, and, as currently understood, it is divided into 3 clades (subfamilies): the Kib...

The Melastomataceae, with ca. 177 genera and 5858 species, are among the ten most species-rich families of angiosperms. Previous molecular phylogenetic analyses have recovered many infrafamilial clades that are incongruent with traditional classifications based on morphology. Here, we present the most taxonomically comprehensive phylogenetic analys...

The Olisbeoideae are a pantropical group comprising six genera and ca. 557 currently recognized species. Members of this subfamily are shrubs or small- to medium-sized trees found mainly in the understory of humid, evergreen forests. The two largest genera, Memecylon and Mouriri, are unlike other melastomes in having apparently 1-nerved leaves. Oth...

The Melastomataceae include some 5858 species predominantly distributed over tropical biomes across the planet. Despite consensus on some particular aspects in the history of the group (e.g., Gondwanan fragmentation does not explain disjunctions), other scenarios have not been fully evaluated (e.g., the role of land bridges), and the impact of mole...

Melastomateae are a diverse pantropical tribe of ~823 species in 44 genera. Members of this tribe range from herbs to medium-sized trees and occupy open and closed habitats in the lowlands to cloud forests. Cochleate seeds with tubercles, a crown of hairs or appendages on the ovary apex and the presence of staminal pedoconnectives with bifurcated v...

Here, we provide an assessment of the variation in both vegetative and reproductive characters within the Melastomataceae, including the subfamilies Olisbeoideae, Kibessioideae, and Melastomatoideae, and the many tribes recognized within the last few decades: an extremely large and diverse clade. These morphological and vegetative anatomical charac...

The genus Cailliella includes a single species, C. praerupticola, restricted to a sandstone plateau region in Coyah, Dubreka, Forécariah and Kindia Préfectures, Guinea, West Africa. Until its rediscovery in 2016, this species was known only by the type gathering made in 1937. We provide an emended description, photographs of living material, locali...

STONE, R.D. (2020). New species of Memecylon (Melastomataceae) from Madagascar: treasures of the TEF Herbarium. Candollea 75: 219–239. In English, English and French abstracts.Memecylon L. (Melastomataceae, Olisbeoideae) is a widespread paleotropical genus of forest shrubs and small trees, and is one of the ten most species-rich genera of woody pla...

Dissotis has long been regarded as the most species-rich genus of African Melastomataceae, yet its diagnostic characters have never been examined in an explicitly phylogenetic context. In a previous study, we recovered a large clade consisting of "Dissotis and allies" but with poorly understood generic limits. Here we present a nearly complete phyl...

Background – A new species of Memecylon (Melastomataceae–Olisbeoideae) from Rwanda, Burundi and western Tanzania is described in connection with preparing the family treatment for the Flore d’Afrique centrale. Methods – Standard herbarium practices were applied.Key results – Memecylon afroschismaticum R.D.Stone is described and illustrated. This ne...

Earlier works recognised two South African species Memecylon bachmannii and M. natalense within M. sect. Buxifolia, but recent molecular analyses have revealed that M. natalense as previously circumscribed is not monophyletic and includes several geographically outlying populations warranting treatment as distinct taxa. In this revision we recognis...

Based on morphological and phylogenetic evidence, a new genus of Melastomataceae (Melastomateae), Nothodissotis Veranso-Libalah & G.Kadereit, gen. nov. , is described from Atlantic Central Africa. Nothodissotis is distinguished from other African Melastomateae genera by its calyx-lobes that are notched at apex and asymmetrical (vs. entire and symme...

Tropical Africa like other tropical ecosystems, although known for their high diversity and endemism remain insufficiently sampled. Focused based studies especially in species-rich groups are vital to improve our current knowledge of African plant diversity. Although molecular methods have been increasingly used over the past two decades to underst...

Warneckea ngutiensis R. D. Stone sp. nov. (Melastomataceae-Olisbeoideae) is described from near Nguti in SW Region, Cameroon. Unique in section Strychnoides in having only a vestigial staminal oil gland, this rainforest shrub is Critically Endangered due to an oil palm plantation project.

Aim African Melastomateae (Melastomataceae) comprise c . 185 species occurring in closed or open habitats throughout sub‐Saharan Africa. We sought to reconstruct biogeographical and habitat history, and shifts in diversification rates of African Melastomateae using a well‐sampled, dated molecular phylogeny. Location Americas, sub‐Saharan Africa, M...

Taxonomy is a scientific discipline that has provided the universal naming and classification system of biodiversity for centuries and continues effectively to accommodate new knowledge. A recent publication by Garnett and Christidis [1] expressed concerns regarding the difficulty that taxonomic changes represent for conservation efforts and propos...

Memecylon sect. Buxifolia R.D. Stone (Melastomataceae, Olisbeoideae) is a group of forest shrubs and small understory trees distributed from tropical East Africa (Kenya and Tanzania) to eastern South Africa and with a disjunct occurrence in Madagascar. Previous authors had recognized three species of this section as occurring in Mozambique, i.e., M...

Molecular phylogenetics is a valuable approach not only for discovering previously undetected plant diversity at the species level, but also for inferring the underlying processes of diversification. In southern Africa, two species of the woody genus Memecylon have been recognised, viz. M. natalense and M. bachmannii, with the range of M. natalense...

Citation: Veranso-Libalah MC, Stone RD, Kadereit G (2017) Argyrella richardsiae, a new species of Melastomataceae from the wet miombo woodlands of south-central Africa. PhytoKeys 82: 113–121. https://doi. Abstract A new species from the wet miombo woodlands of Tanzania and Angola, Argyrella richardsiae Veranso-Libalah & G.Kadereit, sp. nov. (Melast...

Described and illustrated is Warneckea albiflora R.D. Stone & N.P. Tenza, another localized endemic of coastal dry forest near Quiterajo in Mozambique’s Cabo Delgado Province. In Flora Zambesiaca the new species would key to Memecylon sansibaricum Taub. [≡Warneckea sansibarica (Taub.) Jacq.-Fél.], but is distinguished by its elliptic-lanceolate, at...

Lijndenia Zoll. & Moritzi (Melastomataceae, Olisbeoideae) is a small but widespread paleotropical genus of forest shrubs and small trees. In a previous treatment, Jacques-Félix recognized six endemic species of Lijndenia in Madagascar, namely Lijndenia danguyana (H. Perrier) Jacq.-Fél., Lijndenia lutescens (Naudin) Jacq.-Fél., Lijndenia melastomoid...

Melastomateae are the most species-rich (185 spp./13 gen.) and morphologically diverse tribe within the African Melastomataceae. In this study we present the first in-depth phylogenetic analysis of African Melastomateae using sequences generated from one nuclear (nrITS) and two plastid spacers (accD-psaI, psbK-psbL) sampling 183 accessions represen...

Electronic Supplement to Phylogeny and systematics of African Melastomateae (Melastomataceae)

Lijndenia udzungwarum R.D. Stone & Q. Luke, a shrub or small tree of Tanzania's Udzungwa Mountains, is described and illustrated. The placement of the new species in Lijndenia is indicated by its trinervate, papillose-muricate leaves and persistent bracteoles partially fused to form a cupule immediately subtending each flower. The cordate leaves of...

Described and illustrated is Memecylon trunciflorum R. D. Stone, an evidently localized endemic of the Udzungwa Mountains in southern Tanzania. The new species was previously confused with the vegetatively similar but distantly related M. erythranthum Gilg and M. semseii A. Fern. & R. Fern., from which it is distinguished by its anther connectives...

Jacques-Félix (1979) informally recognized the Memecylon normandii Jacq.-Fél. group with three species (M. normandii, M. macrodendron Gilg ex Engl., M. oubanguianum Jacq.-Fél.) from the forests of West and Central Africa. More recently this group has been formally treated as M. section Felixiocylon R.D.Stone. In this paper, four new species are des...

Aim We sought to reconstruct the historical biogeography of the amphi‐Pacific tropical disjunct plant family Symplocaceae in the context of competing Northern Hemisphere (boreotropical) versus Southern Hemisphere (West Gondwanan) hypotheses for its origin and spread. Location Americas, western Pacific Rim, fossil localities in Europe. Methods We...

Under the principle of priority, Memecylon liberiae is the correct name for the West African species previously known as M. aylmeri. A lectotype is designated for M. liberiae from the original material rediscovered in the Berlin herbarium. Use of the neotype designated by Jacques-Félix must therefore be abandoned. A new species M. emancipatum is pr...

The internal and external transcribed spacers of nuclear ribosomal DNA were sequenced in 167 samples of Memecylon s.str. and 22 outgroup samples of Lijndenia, Mouriri, Spathandra, Votomita, and Warneckea. Maximum-likelihood analyses of ETS, ITS1, 5.8S and ITS2 alignments yielded tree topologies that are not significantly incongruent, with one excep...

Warneckea populations from "sand-forest" or "sand-thicket" habitats in Tembe Elephant Park, South Africa, and Licuati Forest Reserve in adjacent southern Mozambique were previously thought to be a small-leaved form of W. sousae, which typically includes larger-leaved plants ranging from central Mozambique northward to Tanzania. We examine this hypo...

Described and illustrated is Warneckea cordiformis R. D. Stone, an evidently localized endemic of coastal dry forest in Mozambique's Cabo Delgado Province. In ‘Flora Zambesiaca’ the new species would key to W. sansibarica (Taub.) Jacq.-Fél., from which it is readily distinguished by the much smaller, ovate to cordiform leaves and white, short-pedic...

Background and aims - Further studies of Madagascan Memecylon have revealed that much of the herbarium material collected in the last 25 years is undescribed. As a prelude to a comprehensive taxonomic revision, the current paper presents an overview and analysis of the remarkable diversity of this genus in Madagascar. Key results - Within the paleo...

Warneckea consists of shrubs and small trees endemic to tropical forests in Africa, Madagascar, and Mauritius. Phylogenetic analyses of sequence data from the transcribed spacers of nuclear ribosomal DNA (ETS, ITS) indicate that W. sect. Carnosa Jacq.-Fél. (1 sp., East Africa and Madagascar) is a divergent element that is best treated at subgeneric...

Warneckea consists of shrubs and small trees endemic to tropical forests in Africa, Madagascar, and Mauritius. Phylogenetic analyses of sequence data from the transcribed spacers of nuclear ribosomal DNA (ETS, ITS) indicate that W. sect. Carnosa Jacq.‐Fél. (1 sp., East Africa and Madagascar) is a divergent element that is best treated at subgeneric...

Dans ce travail est décrit et illustré Memecylon batekeanum R. D. Stone & G. M. Walters du zone tampon du Parc National des Plateaux Batéké du Sud-est Gabon. Cette nouvelle espèce se rapproche de l'espèce Camerounaise M. amshoffiae Jacques-Félix, mais s'en distingue par sa forme d'arbrisseau, ses jeunes rameaux 4-angulaires-ailés, ses cymes peu fle...

Results of recent morphological and molecular analyses necessitate the transfer of the species originally described as Memecylon melindense A.Fern. & R.Fern. to the genus Warneckea Gilg. A new combination, Warneckea melindensis (A.Fern. & R.Fern.) R.D.Stone & Q.Luke is proposed, and an IUCN status of Endangered is assessed for this regional endemic...

Described and illustrated is Warneckea austro-occidentalis R. D. Stone, an endemic of tropical forests in Cameroon’s South West Province and adjacent Nigeria. The name W. mangrovensis (Jacq.-Fél.) R. D. Stone is also proposed at species level for the taxon originally described as W. fascicularis var. mangrovensis Jacq.-Fél. An IUCN (2001) status of...

Seven new names at species rank are proposed in Memecylon sect. Afzeliana Jacq.-Fél., a group of forest shrubs and small trees confined to Guineo-Congolian Africa. The group is centred in Cameroon, where 17 of the 20 species occur. A new flower type, the “star-flower” in Memecylon is revealed, and its taxonomic and ecological importance discussed....

Evidence is presented for phylogenetic relationships in pantropical Melastomataceae, subfamily Olisbeoideae based on combined exon and intron sequences of the nuclear glyceraldehyde 3-phosphate dehydrogenase gene. Parsimony and maximum-likelihood analyses yielded a well-supported ingroup tree consistent with earlier morphologically based concepts o...

Eight new species of Memecylon L. are described and illustrated from Madagascar (M. acrogenum, M. sejunctum, M. pterocladum, M. xiphophyllum, M. perditum, M. impressivenum, M. interjectum, M. amplifolium) together with one new spe- cies of Warneckea Gilg (W. masoalae). Also described is Memecylon mayottense, a new species from Mayotte (Comoro islan...

Thesis (Ph.D. in Integrative Biology)--University of California, Berkeley, Fall 2004. Includes bibliographical references (leaves 184-198).