Trevor Edwards

• La Trobe University

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The potential impacts of climate change on mountain environments are gaining increasing attention given the inherent fragile nature and high biodiversity value of mountain biota. We pay particular attention to the soil–plant–climate interface given that such interactions and trade-offs may exert a strong influence on how plant species will respond...

The Afromontane phytochorion is a region delineated on the basis of shared plant species distributions and centres of plant endemism occurring mainly in the high elevation regions of sub-Sahelian Africa. We have provided in this study a synthesis of the various contexts in which the Afromontane concept has been applied in the past, highlighting man...

A new South African endemic species, Gerbera sylvicola is described and illustrated, with data provided on its morphology, ecology and distribution. The species appears to be closely related to G. kraussii and whilst it shares felted and prominently veined abaxial leaf surfaces, several ecological, reproductive and vegetative features clearly disti...

We made use of pot experiments and soil mineralisation assays to test the effect of temperature on the soil nitrogen (N) economy of the Drakensberg Alpine Centre ('mountain site'). The approach was enhanced by the inclusion of a contrasting warm, subtropical environment on the east coast of southern Africa ('coast site') which presented an opportun...

The inference of phylogenetic relationships is often complicated by differing evolutionary histories of independently‐inherited markers. The causes of the resulting gene tree incongruence can be challenging to identify, often relying on coalescent simulations dependent on unverifiable assumptions. We investigated alternative techniques using the S...

DRIMIA COOPERI IN KWAZULU-NATAL, AND THE ETHNOMEDICINAL TRADE

Within the South African Plectranthus species two specialized lines of corolla adaptations have evolved. Long-proboscid flies (Nemestrinidae) appear to have driven the development of Plectranthus species with long corolla tubes that are limited to the sub-continent. Plectranthus s.l. (including Coleus) species with sigmoid corollas are far more wid...

We address the generic limits of Gnidia (Thymelaeaceae) through a phylogenetic analysis of nuclear ribosomal DNA internal transcribed spacer (ITS) and plastid rbcL, trnL intron and trnL-F intergenic spacer regions. Maximum parsimony and Bayesian inference were used to produce trees and assess internal support. The most significant conclusion drawn...

Species boundaries in rapidly evolving lineages are often blurred, necessitating analysis of the full range of variation within a complex in order to identify traits that can be used to diagnose taxa. The delimitation of Bonatea speciosa (L. f.) Willd. has been controversial, as most, but not all, recent authors have included within the concept of...

Question: What is the long‐term compositional response of grass and forb species to various combinations of burning and mowing? Can these responses be predicted from simple plant traits? Location: Ukulinga research and training farm (24°24′E, 30°24′S), Pietermaritzburg, KwaZulu‐Natal, South Africa. Methods: Grass species relative abundance in 1996...

Two new rosulate species of Streptocarpus are described from the eastern seaboard of South Africa. The first is endemic to Mpumalanga Province. This species has almost actinomorphic corollas with small cylindrical tubes and was previously included within Streptocarpus parviflorus. However, molecular and morphological data and habitat preference do...

lobally, many nations are legislating access for bioprospecting purposes to their biological and genetic resources. South Africa, as a megadiverse country, has recently regulated bioprospecting, access and benefit-sharing activities in accordance with its obligations as a ratifying party to the Convention on Biological Diversity. The context and pr...

Regression analyses of local medicinal floras are considered potentially useful when prioritising candidate plant taxa for pharmacological/bioprospecting investigations. To identify plant orders and subsequently families within the highly diverse ethnomedicinal flora of southern Africa, towards which biases by traditional healers are demonstrable....

Taxa with large geographical ranges often exhibit clinal variation. Detailed morphometric analysis may be required to establish species boundaries in such taxa. The extensive morphological variation within the Bonateacassidea complex (comprising the closely related taxa Bonatea cassidea Sond. Bonatea saundersiae (Harv.) T. Durand & Schinz and Bonat...

A new species, Ledebouria mokobulanensis from Mpumalanga, is described and illustrated. Its alliances with its closest ally, L. galpinii, are discussed.

CRASSULA STREYI RECORDED FROM THE EASTERN CAPE, SOUTH AFRICA

A NEW PYROPHYTIC LACHENALIA SPECIES (MASSONIEAE) FROM WESTERN CAPE, SOUTH AFRICA

Invitro germination as a conservation aid demands propagation systems that yield increasingly larger numbers of plants as rapidly as possible. However, summer-rainfall Disa species are germinated infrequently under asymbiotic conditions. Attempts to bypass impermeable testae in these species resulted in the formulation of a dual-phase protocol—with...

Gene flow through pollen and seed dispersal is important in terms of population differentiation and eventually speciation. Seed and pollen flow are affected in turn by habitats and pollen vectors. We examined the effect of different pollinators and habitats on gene flow by comparing two species of Streptocarpus, using microsatellite and chloroplast...

Bonatea bracteata G.McDonald and McMurtry and Bonatea tentaculifera Summerh. were recently transferred to the genus Habenaria, as Habenaria transvaalensis Schltr. and Habenaria bonateoides M.Ponsie respectively. Until now H. bonateoides was known only from the holotype collected at Nairobi National Park in Kenya but new collections of the species f...

The genus Bonatea is widely distributed throughout southern and eastern Africa. Considerable debate surrounds the generic status of Bonatea, but there have been neither previous studies of evolutionary relationships among Bonatea species, nor any tests of the monophyly of the genus in relation to its close relative Habenaria. We investigated phylog...

The diagnostic characters for Bonatea Willd. (Orchidaceae) are re-evaluated. The genus is distinguished from Habenaria by the possession of a galeate rostellum, which is clearly separated from the vertical anthers, and a tooth in the spur mouth (secondarily lost in Bonatea rabaiensis (Rendle) Rolfe). Morphological evidence suggests that Bonatea bra...

A new species, Disa vigilans D. McMurtry and T.J. Edwards, is described from the Mpumalanga Escarpment. The species is a member of the Disa Section Stenocarpa Lindl. Its alliances are discussed in terms of its morphology and its phylogenetic placement is elucidated using molecular data. D. vigilans has previously been considered as an anomalous for...

Sexual polymorphism was studied in the shrub Gnidia wikstroemiana (Thunb.) Meisn. from the semiarid Nama Karoo Biome, South Africa. The populations comprised plants bearing either female flowers, or hermaphrodite flowers with variable female function. In two populations, female plants accounted for 36–37% of the flowering plants. Female flowers wer...

This is the sixth in a series of papers on Lachenalia, towards a revision of the genus. Three new species are described, L. lutea from the southwestern part of the Western Cape, L. cernua from the southern Cape Peninsula and the Worcester Valley of the Western Cape, and L. nardousbergensis from the Bokkeveld Plateau of the Northern Cape, and the Na...

We attempted to ascertain the most effective sample size for monitoring serial changes in the herbaceous layer of fragmented and neglected grasslands that are responding to annual veld burning. We conducted a sampling exercise in a coastal grassland invaded by the alien shrub Chromolaena odorata (chromolaena) and other indigenous woody species, fro...

Many Disa species (80%) have not been germinated in vitro, fuelling conservation fears. Winter-rainfall species are typically germinable, whilst summer-rainfall species are exclusively intractable in vitro. We aimed to establish the in vitro germination requirements for previously ungerminated Disa species. Conventional asymbiotic seed culture prot...

Two new species of Lamiaceae are described from South Africa. Thorncroftia lotterii T.J. Edwards and D. McMurtry is described from the mountains that divide Mpumalanga and Swaziland. The species appears to be endemic to the Ugutugulu River Gorge and is closely allied to T. succulenta (R.A. Dyer and E.A. Bruce) L.E. Codd and T. media L.E. Codd. Tetr...

The essential oil composition is reported for Plectranthus ciliatus, Plectranthus zuluensis and their putative hybrid. The essential oil chemistry is in support of morphological data and pollination studies, which have indicated a natural hybrid between P. ciliatus and P. zuluensis. The hybrid plant contains terpenoids from both putative parents to...

The Drakensberg Alpine Centre (DAC) of southern Africa supports a speciose number of angiosperms. Its compliment of 2520 native angiosperms is comparable with the native floras of northern hemisphere countries such as Germany or Switzerland, and is almost double that of Great Britain. Levels of angiosperm endemism and near-endemism in the DAC too a...

Six different floral morphologies can be found among the ca. 146 species of Streptocarpus occurring in Africa and Madagascar. One of these, a simple, small pouch type, was found to be plesiomorphic for the genus after mapping these floral types onto a molecular phylogeny. The breeding systems and population structure of three species possessing the...

We describe a scenario of plant speciation across a relict forest archipelago in South Africa involving Pleistocene habitat expansion-contraction cycles, dispersal and adaptation to lower temperatures. This is the first population level study using molecular data in South African forests and has significant implications for conservation efforts in...

Two newly discovered species of Plectranthus L'Hér. are described from the Pondoland Centre of Plant Endemism, on the eastern seaboard of South Africa. P. brevimentum and P. stylesii are exceedingly narrow endemics known only from their type localities. The known distribution ranges of two other narrow endemics of the region, P. ernstii and P. prae...

A synopsis and key to South African species of Argyrolobium Eckl. & Zeyh. are presented. South Africa constitutes the centre of diversity for the genus and 47 species are recognised. Full synonymy and typification of the South African species are provided, with diagnostic characters, distribution maps and illustrations.

The history, taxonomy, distribution and cultivation requirements of the South African Lachenalia sargeantii W.F.Barker are discussed; a full botanical description, illustration and habitat photograph are provided.

A new species of Streptocarpus (S. lanatus MacMaster) is described from central Madagascar. Material referable to this new taxon was previously assigned to S. ibityensis Humbert, from which it can be distinguished by its densely woolly leaves, smaller corolla lobes with purple markings, and lack of staminodes. It is endemic to Mt Itremo, where it g...

The horticulturally important and botanically diverse genus Lachenalia Jacq. f. ex Murray is endemic to southern Africa, and is the largest member (115 species) of the Hyacinthaceae. The genus is morphologically and cytologically variable. Species delimitation is usually unambiguous but in some instances there is gradation between species. Other sp...

A new species, D. flagellaris, is described and illustrated. This species appears to be closely allied to D. calcarata and shares semiepigeal bulbs and evergreen, terete leaves distinguished by their much larger size. No intermediates occur between D. flagellaris and sympatric individuals of D. calcarata. The new species is endemic to the Krantzklo...

A new species of Streptocarpus (S. lanatus MacMaster) is described from cen-tral Madagascar. Material referable to this new taxon was previously assigned to S. ibityensis Humbert, from which it can be distinguished by its densely woolly leaves, smaller corolla lobes with purple markings, and lack of stami-nodes. It is endemic to Mt Itremo, where it...

Stenobasipteron wiedemanni, a long-proboscid nemestrinid fly, services a Guild of flowers distinct from the Prosoeca ganglbaueri pollination Guild in which it has previously been placed. The former fly is the recorded pollinator of 19 plant species in six families: the Acanthaceae, Balsaminaceae, Gesneriaceae, Iridaceae, Lamiaceae, and Orchidaceae....

Plants with highly specialized pollination systems may be particularly vulnerable to the effects of habitat fragmentation. The sub-canopy tree Oxyanthus pyriformis subsp. pyriformis has deep tubular flowers (c. 90 mm in length) that are specialized for pollination by long-tongued hawkmoths. Existing natural populations of this taxon appear to be co...

Disturbance may be an important determinant of plant community composition and diversity owing to its effects on competitive interactions, resources, dominance and vigour. The effect of type, timing and frequency of disturbance on grass and forb species richness was examined using data from a long-term (> 50 yr) grassland burning and mowing experim...

Disturbance may be an important determinant of plant community composition and diversity owing to its effects on competitive interactions, resources, dominance and vigour. The effect of type, timing and frequency of disturbance on grass and forb species richness was examined using data from a long-term (> 50 yr) grassland burning and mowing experim...

The Drakensberg Alpine Centre (DAC) comprises the 40,000km 2 high-altitude range of hills, mountain peaks and escarpment plateau bordering the eastern interior of southern Africa. Renowned for its species-rich flora and high levels of endemism, the DAC is here shown to support over 2800 specific and infraspecific native taxa, with c.16% of the angi...

Microsatellite markers have been developed from standard enriched genomic libraries and a cDNA library for the genus Streptocarpus. Out of 15 loci derived from ESTs (expressed sequence tags), four gave working primer pairs, with expected heterozygosities (HE) ranging from 0.42 to 0.86. Out of 89 genomic library derived loci, 6 gave working primer p...

Three taxa of Ledebouria Roth are raised from synonymy to species status, with notes, diagnostic characters and distributions. L. galpinii (Baker) S.Venter & T.J. Edwards is a narrow endemic in the Wolkberg Centre and was formerly placed within L. cooperi (Hook.) Jessop. The other species, L. sandersonii (Baker) S.Venter & T.J. Edwards and L. ensif...

The new species Streptocarpus lilliputana (Gesneriaceae), collected on the Pondoland coast, South Africa, is described. Although its alliances are not obvious in terms of corolla morphology and rosulate habit, it approaches S. gardenii and its allies. The pollen and stigma of S. lilliputana differ markedly from the stenopalynous grains and bilobed...

A new species of the Streptocarpus rexii aggregate is described from Itala Game Reserve in KwaZulu-Natal, South Africa. The geographic isolation of S. kunhardtii, its pale methyl violet flowers, and long fruits distinguish it from S. roseoalbus, its closest relative. A second new species, S. hilburtianus, is described from two high-altitude localit...

The essential oil composition is reported for Plectranthus ciliatus, Plectranthus zuluensis and their putative hybrid. The essential oil chemistry is in support of morphological data and pollination studies, which have indicated a natural hybrid between P. ciliatus and P. zuluensis. The hybrid plant contains terpenoids from both putative parents to...

A checklist of the plants of Mahwaqa Mountain, KwaZulu-Natal, is presented. The list includes 1 030 indigenous and naturalized flowering plants and ferns. Comparisons are made with the floras of KwaZulu-Natal (Ross 1972), the Cape of Good Hope Nature Reserve, Cape Point (Taylor 1985), the southern Natal Drakensberg (Hilliard & Burtt 1987), the Amat...

A NEW SPECIES OF LACHENALIA FROM NAMAQUALAND. SOUTH AFRICA

The evolution of pollination systems has been investigated in Zaluzianskya section Nycterinia (Scrophulariaceae), a group characterized by very long-tubed flowers (up to 60 mm) that open either only at night (19 species) or during the day (one species). Field observations of three species: Z. natalensis, Z. elongata and Z. pulvinata, revealed that...

Seed germination is consistently poor for the majority of Disa species, with in vitro culture revealing a decrease in species germinability as one moves from the winter to the summer-rainfall areas of South Africa. In an effort to enhance seed culture as a means of promoting conservation in Disa, the seed testa is highlighted as a regulatory factor...

Morphological, anatomical and morphometric studies of leaf and bract diversity among selected species of Gnidia (Thymelaeaceae) were conducted. Surface details of fresh and herbarium-dried leaves and bracts were examined using Light Microscopy and Scanning Electron Microscopy. Intraspecific and interspecific variation of leaves and bracts based on...

Long, narrow corolla tubes have evolved several times in genera of southern African Lamiaceae, such as Plectranthus, Thorncroftia, Orthosiphon, Hemizygia, Stachys and Salvia. A study of the pollination of Plectranthus in KwaZulu-Natal and the Eastern Cape of South Africa showed a nemestrinid fly, Stenobasipteron wiedemanni, to be the pollinator of...

The heathy, sclerophyllous vegetation type known locally in South Africa as 'fynbos' is not restricted to the Cape Floral Kingdom (CFK), but occurs throughout sub-Saharan Africa, Madagascar and the Mascarene Islands. The fynbos shrublands of these regions occur mostly in cool, montane environments where rainfall is high and soils are highly leached...

A number of examples exist of Gnidia species closely resembling each another, and possibly being synonymous. Many such species have been established on the basis of other non quantitative differences in character variation, but no studies have tested the validity of morphometric data in distinguishing taxa in this genus. In addition, no studies in...

Plectranthus porphyranthus, a new species from Zimbabwe, is described. The alliances between the new species, and P. venteri, P. grandidentatus and P. hadiensis are discussed.

Taxa recognised in this revision are: Calpurnia aurea (Aiton) Benth. subsp. aurea; C. aurea (Aiton) Benth. subsp. indica Brummitt; C. floribunda Harv.; C. glabrata Brummitt; C. intrusa (R.Br. in W.T. Aiton) E.Mey.; C. reflexus A.J.Beaumont sp. nov.; C. sericea Harv. and C. woodii Schinz. A putative hybrid between C. sericea and C. woodii is recorde...

The genusPlectranthus (Lamiaceae) shows remarkable radiation on the sandstones of southern Natal and northern Transkei in South Africa, where six endemic species occur. Two of these endemic species,P. hilliardiae andP. oribiensis, are included in this study, as well asP. reflexus, for which only limited data are available. The other species that we...

A revision of Ledebouria in South Africa has revealed a number of undescribed species. This paper deals with two new species, Ledebouria atrobrunnea S. Venter and L. dolomiticola S. Venter. Both species possess cylindrical bulbs, erect leaves (rare in Ledebouria) and prominent shoulders on the carpel apices. These synapomorphies are also seen in L....

Two endemic Ledebouria Roth species are described with notes, diagnostic characters, distributions and alliances. L. crispa appears to be allied to L. socialis (Baker) Jessop with which it shares densely gregarious, epigeal bulbs and L. undulata (Jacq.) Jessop of the Northern and Western Cape which shares crispate leaf margins. L. parvifolia is end...

Four new Plectranthus taxa from South Africa are described: P. malvinus Van Jaarsv. and T.J.Edwards, P. saccatus subsp. pondoensis Van Jaarsv. and S.Milstein, P. purpuratus subsp. tongaensis Van Jaarsv. and T.J.Edwards and P. purpuratus subsp. montanus Van Jaarsv. and T.J.Edwards. P. aliciae (Codd) Van Jaarsv. and T.J.Edwards and P. lucidus (Benth....

The taxonomy of A. speciosum Eckl. and Zeyh and its close allies, from the eastern parts of South Africa, is revised. A new species, A. robustum T.J. Edwards, is described. This taxon is closely allied to A. speciosum but is allopatric and morphologically distinct. The description of A. baptisioides (E.Mey.) Walp. is amended to embrace A. sutherlan...

During a re-evaluation of the taxonomy of Streptocarpus cyaneus S. Moore it became apparent that an entity intermediate between that species and S. primulifolius Gand. deserves formal recognition, and it is described as S. floribundus. In addition, the subspecies of S. primulifolius are raised to species rank as S. formosus (Hilliard & Burtt) T.J....

The pollination syndromes ofLeonotis (Pers.)R. Br. are discussed. Ornithophily accounts for most of the nutlets set in perennialLeonotis species but in the annual species [L. nepetifolia (L.)R. Br.] autogamy prevails.Leonotis species are predominantly pollinated by a variety of sunbirds, although bees are also involved. Nectar is sucrose-dominant i...

A new species, Argyrolobium pseudotuberosum T.J. Edwards, is described and its alliance with other tuberous herbaceous species within the genus is outlined. The taxonomy of A. longifolium (Meissner) Walp. is clarified.

A new species of Crossandra is described and its alliances are discussed. The distributions of Crossandra species within South Africa are given. Diagnostic aspects of bract vestiture and seed scales are highlighted and a key is provided for South African species.

The genus Buchenroedera Eckl. & Zeyh. is subdivided into two sections, Racemosa and Buchenroedera. Sectional characters are discussed and the Natal members of section Racemosa are revised.

A new genus, Salpinctium T.J. Edwards, is distinguished from Asystasia Blume by its elongate, linear corolla and bilateral pollen. The following new combinations are made : S. stenosiphon (Clarke) T.J. Edwards and S. natalense (Clarke) T.J. Edwards. S. hirsutum T.J. Edwards is a new species.

Asystasia pinguifolia T.J. Edwards, a succulent strand plant recorded from the eastern coast from Tanzania to northern Natal, closely allied to the African form of A. gangetica (L.) T. Anders., is described. Its succulent, amphistomatic leaves, decussate inflorescence and smaller flowers, distinguish it from A. gangetica.