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  • School of Life Sciences
    University of KwaZulu-Natal
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    South Africa
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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.... more
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
bearing a dorsal oil-gland and by its ellipsoid to obovoid fruits (vs anther connective gland absent and fruits globose
in M. erythranthum and M. semseii). The new species is placed in M. sect. Magnifoliata R. D. Stone together with M. magnifoliatum A. Fern. & R. Fern., from which it differs by its smaller leaves mostly 9.5–15.0 x 3.5–6.0 cm (vs 18–35 x 8–13 cm), transverse veins 8–18 pairs (vs 25–28 pairs), short-pedunculate inflorescences with secondary axes
well developed (vs peduncles and secondary axes absent), white flowers (vs bluish purple), and smaller fruits mostly 11.5–
14.5 x 9–11 mm on longer fruiting pedicels 8.0–13.5 mm (vs fruits 17–20 x 12–14 mm on pedicels 5.0–7.5 mm). Despite its local endemism, Memecylon trunciflorum has been assessed as ‘Least Concern’ according to IUCN criteria, although this assessment is dependent on the continued safeguarding of the Udzungwa Mountains National Park.
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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... more
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 L. udzungwarum are unique in the genus. From the East African L. brenanii (A. Fern. & R. Fern.) Jacq.-Fél. and L. procteri (A. Fern. & R. Fern.) Borhidi, the new species is further distinguished by its capitellate inflorescences on long, filiform, axillary peduncles,
resembling those of the Sri Lankan L. capitellata (Arn.) K. Bremer. Despite its local endemism, L. udzungwarum has been
assessed as ‘Least Concern’ according to IUCN criteria, although this assessment is dependent on the continued safeguarding
of the Udzungwa Mountains National Park. An identification key is provided for the three currently recognized Tanzanian
species of Lijndenia.
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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... more
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 described and illustrated for this section: M. korupense R.D.Stone, sp. nov. (South-West Region, Cameroon), M. fugax R.D.Stone, sp. nov. (South Region, Cameroon), M. alipes R.D.Stone, sp. nov. (Woleu-Ntem Province, Gabon & South Region, Cameroon), and M. biokoense R.D.Stone, sp. nov. (Bioko Sur Province, Equatorial Guinea). A lectotype is designated for M. macrodendron. New country-records are reported or confirmed for M. normandii (Nigeria), M. oubanguianum (Gabon, Congo-Kinshasa), and M. macrodendron (Gabon, Congo-Brazzaville). A key to the species of M. section Felixiocylon is provided, together with an assessment of conservation status for each species according to the criteria of the IUCN.
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Aim: We sought to reconstruct the historical biogeography of the amphi-Pacifictropical disjunct plant family Symplocaceae in the context of competing Northern Hemisphere (boreotropical) versus Southern Hemisphere (West Gondwanan)... more
Aim: We sought to reconstruct the historical biogeography of the amphi-Pacifictropical 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 derived a dated phylogeny using a relaxed clock on a data set of114 terminals, four genic regions (three plastid regions and the nuclear ribosomal internal transcribed spacer region) and six fossil calibrations. We inferred ancestral geographical ranges with maximum likelihood under a dispersal–extinction–cladogenesis model, with the probability of dispersal constrained by areal distance and palaeogeography.
Results: We inferred a Eurasian origin for crown-node Symplocaceae at c. 52 Ma, followed by dispersal to North America (including Mesoamerica) at c. 52–38 Ma. Most of the highest likelihood intra-American dispersals recovered in the analysis trended from north to south, with none from south to north. Six intra-American dispersals were inferred to have originated in North America, with lineages either terminating in the Antilles or migrating to South America at various times. One additional North American lineage emigrated back to Eurasia in the late Miocene.
Main conclusions: The predominantly southwards American migrations inferred here for the Symplocaceae conform to the boreotropics hypothesis, apparently driven by cooling and drying climates in the later Cenozoic. The inferred Eurasian origin for the family corroborates a more specific European origin, as suggested independently by its fossil fruit record. Of the lineages ultimately arriving in South America from North America, two are inferred to have migrated through the Antilles (by island-hopping) and three through Mesoamerica. The timing of one of the Mesoamerican events, inferred to be between 8.9 and 7.5 Ma, implies over-water dispersal under the prevailing model of Isthmus of Panama formation, but also accords with overland migration under a model of earlier formation.
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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... more
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 proposed to replace M. liberiae sensu Jacques-Félix. A revised identification key is provided for the West African species of Memecylon sensu stricto.
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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... more
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 exception involving the Tanzanian sample Luke 9741. Monophyly of Memecylon s.str. is strongly supported in the separate ETS and the combined ETS + ITS1 + 5.8S + ITS2 analyses. Also supported in all analyses except 5.8S is a sister-group relationship between a small species-group from western and central Africa (Memecylon subg. Mouririoidea, ovary 4-loculed) and the remaining taxa (M. subg. Memecylon, ovary unilocular). In the combined analysis, internal branches at the base of M. subg. Memecylon are short and weakly supported, yet within this large subgenus one finds a series of monophyletic groups representing different parts of the widespread paleotropical distribution (one group in western and central Africa; two separate groups in East Africa, one of these extending to southern Africa and disjunctly to western and northern Madagascar; one species-rich group occurring exclusively on Madagascar and the neighboring Comoro and Mascarene islands; and three distinct groups in Indo-Malesia, one of these also including the Seychelles endemic M. elaeagni). Within the western and central African clade, M. sect. Polyanthema sensu Jacques-Félix is paraphyletic with respect to M. sect. Afzeliana, and at the morphological level it seems to be a group defined by symplesiomorphies (ovary unilocular, fruit globose). Three East African species (M. fragrans, M. greenwayi, M. semseii) are returned to Memecylon s.str. after being erroneously transferred to Lijndenia by Borhidi. T he Madagascan endemic M. mocquerysii is no longer considered a taxonomic synonym of the distantly related, Tanzanian M. cogniauxii. In addition to elevating M. sect. Mouririoidea to subgeneric rank, the following changes are proposed in the infrageneric classification of African Memecylon: (1) the circumscription of sect. Polyanthema is narrowed to comprise only the members of the “M. polyanthemos complex” sensu Jacques-Félix; (2) Engler’s sections Tenuipedunculata, Cauliflora, and Obtusifolia are re-instated with emended descriptions (in the case of sect. Cauliflora with an expanded circumscription); (3) seven new sections, Buxifolia, Diluviana, Felixiocylon, Germainiocylon, Magnifoliata, Montana, and Sitacylon, are described; (4) the purported occurrence of M. sect. Pseudonaxiandra in East Africa is rejected. A key is provided to the two subgenera and twelve sections currently recognized in African Memecylon. Further study is needed toward a sectional classification of Indo-Malesian Memecylon, and for revision of the seven Madagascan sections recognized by Jacques-Félix.
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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 formof W. sousae, which... more
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 formof W. sousae, which typically includes larger-leaved plants ranging from central Mozambique northward to Tanzania. We examine this hypothesis using molecular and morphological evidence. Maximum-likelihood phylogenetic analysis of combined nrDNA ETS and ITS sequence data failed to resolve W. sousae and the Maputaland populations as an exclusively monophyletic group. Instead, the Kenyan endemic W. mouririifolia was strongly supported as the sister species of W. sousae, and the Maputaland plants were resolved in a separate, strongly supported clade together with populations of an as-yet undetermined Warneckea species from northern Mozambique. A hypothesis of exclusive monophyly for the plants from Tembe and Licuati had moderate support in separate ETS and ITS1 analyses (bootstrap proportions of 88% and 81%, respectively). Statistically significant differences in leaf dimensions and internode length were found between the Maputaland plants and typical W. sousae. We conclude that the populations from Tembe and Licuati represent a distinct species, which we describe as W. parvifolia. The species differs from W. sousae in having shorter internodes (mostly 5–25 mm not 10–60 mm long), smaller leaves (mostly 14–32 × 8–19 mm not 40–76 × 22–52 mm), shorter petioles (mostly 1–1.5 mm not 1.5–6 mm long), smaller flowers (hypanthium 1 × 1.5–1.75 mm not 1.5–2 × 2 mm; calyx lobes 0.5 mm not 0.75 mm long; staminal filaments 3–4 mm not 5 mm long; style 4–5 mm not 9 mm long), and globose fruit (not obovoid). An IUCN conservation status of Endangered (EN) B1a, b(ii, iii) is indicated for W. parvifolia, due to its limited distribution and projected declines in its habitat quality and area of occupancy.
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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.)... more
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-pedicellate flowers. Because of its evidently very limited occurrence as well as on-going anthropogenic threats, Warneckea cordiformis is here assessed as ‘Critically Endangered’ (CR) B1a,b(iii) according to IUCN criteria. A key is provided to the Mozambican species of Warneckea.
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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... more
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 paleotropical distribution of Memecylon, Madagascar contains by far the highest concentration of species proportionate to land area. All of the Madagascan Memecylon species are endemic to the island, with the majority being localized endemics known from just one or two sites. As a result of recent field- and collections-based studies, about fifty new species will be proposed. When this is done the total number of Madagascan Memecylon species will increase to 138 (representing a 70% increase from our state of knowledge in 1985). Memecylon is clearly one of the plant genera that has radiated extensively on the island. Floral morphology is strongly conserved, but leaf morphology and inflorescence position are quite variable and often diagnostic at the species level. In several cases, different species have converged on similar vegetative morphologies, leading to taxonomic confusion.
Conclusions – When making species determinations in Madagascan Memecylon, both morphological features and ecogeographic factors should be taken into account. Comprehensive taxonomic revisions in species-rich groups like Memecylon are a prerequisite for further study of the mechanisms of species diversification on the island.
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This note proposes new combinations at species rank for the taxa originally described as Memecylon pedunculatum var. centrale Jacq.-Fél. and Memecylon eglandulosum var. bezavonense Jacq.-Fél. A lectotype is also designated for the latter.
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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.... more
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. Carnosae Jacq.-Fél. (1 sp., East Africa and Madagascar) is a divergent element that is best treated at subgeneric level. The analyses recovered three major lineages in W. subg. Warneckea, together forming a basal trichotomy. The three lineages represent W. sect. Strychnoides (western and central Africa), sect. Warneckea (East Africa, Madagascar, Mauritius), and a third group with three West African species (W. fascicularis, W. guineensis, W. mangrovensis) comprising the newly proposed W. sect. Guineenses.
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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... more
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 endangered is assigned for both W. austro-occidentalis and W. mangrovensis.
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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. &... more
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 of coastal forests in Kenya and Tanzania. There is no evidence of hybridisation between W. melindensis and the closely related W. sansibarica (Taub.) Jacq.-Fél., even in sites where the two species are sympatric.
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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... more
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. Three new, locally endemic species from the South West Province of Cameroon are described, mapped and illustrated: M. kupeanum R. D. Stone, Ghogue & Cheek, M. bakossiense R. D. Stone, Ghogue & Cheek, and M. rheophyticum R. D. Stone, Ghogue & Cheek. Two new names, M. accedens R. D. Stone, Ghogue & Cheek and M. hyleastrum R. D. Stone & Ghogue and one new combination, M. mamfeanum (Jacq.-Fél.) R. D. Stone, Ghogue & Cheek are provided at species level for three taxa originally proposed as varieties of M. afzelii G. Don. The taxon M. arcuatomarginatum var. simulans Jacq.-Fél. is also elevated to species status, as M. simulans (Jacq.-Fél.) R. D. Stone & Ghogue. Conservation assessments are provided for all the newly named taxa. A key is provided to the species of Memecylon sect. Afzeliana.
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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... more
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 of six genera—Memecylon, Mouriri, Votomita, Spathandra, Lijndenia, and Warneckea. The position of the root node in Olisbeoideae remains equivocal. Outgroup-rooted maximum parsimony suggests a deep divergence between Old and New World lineages, while the maximum-likelihood rooting resolved paleotropical genera as a paraphyletic grade basal to the neotropical taxa. The Fitch optimization method for estimating character evolution consistently inferred the strongly acrodromous leaf venation pattern as ancestral in Olisbeoideae, reinforcing the conclusion that the superficially uninervate or brochidodromiform venation pattern of Memecylon, the neotropical subclade, and some Lijndenia and Warneckea species is best interpreted as a series of independent losses of the strongly acrodromous condition. Genomic GapC sequences may have phylogenetic utility at intergeneric level in other angiosperm families, particularly those that have low apparent rates of chloroplast DNA sequence evolution.
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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 species of... more
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 species of Warneckea Gilg (W. masoalae). Also described is Memecylon mayottense, a new species from Mayotte (Comoro islands).
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Described and illustrated is Memecylon batekeanum R. D. Stone & G. M. Walters from the buffer zone of the Batéké Plateaux National Park in southeastern Gabon. This new species is closely related to M. amshoffiae Jacques-Félix of Cameroon,... more
Described and illustrated is Memecylon batekeanum R. D. Stone & G. M. Walters from the buffer zone of the Batéké Plateaux National Park in southeastern Gabon. This new species is closely related to M. amshoffiae Jacques-Félix of Cameroon, but is distinguished by its shrubby habit, quadrangular-alate young branchlets, fewer-flowered inflorescences, and calyptrate calyx. A provisional IUCN status of Vulnerable is assigned. Memecylon amshoffiae was treated earlier in section Mouririoidea Jacques-Félix, but this is contraindicated by evidence from ovary and anther morphology and by recent molecular phylogenetic analyses. Together, M. amshoffiae and M. batekeanum are provisionally placed next to M. diluviorum Exell in section Polyanthema Engler.
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