Olwen M. Grace

Olwen M. Grace
Royal Botanic Gardens, Kew · Comparative Plant & Fungal Biology

PhD

About

74
Publications
89,639
Reads
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2,415
Citations
Introduction
My research focuses on the evolution of utility plants, using a phylogenetic approach to understand patterns in the ways people value plant diversity. I currently focus on succulent plants and arid regions where changing climates will influence the future value of arid-adapted plants.
Additional affiliations
December 2014 - May 2017
Royal Botanic Gardens, Kew
Position
  • Research Leader
August 2010 - July 2012
University of Copenhagen
Position
  • Marie Curie Fellow
January 2003 - January 2004
South African National Biodiversity Institute
Education
January 2005 - September 2009
University of Pretoria
Field of study
  • Plant Science
January 2000 - December 2002
University of KwaZulu-Natal
Field of study
  • Botany
January 1996 - December 1999
University of KwaZulu-Natal
Field of study
  • Botany

Publications

Publications (74)
Preprint
Full-text available
Succulence is an adaptation to low water availability characterised by the presence of water-storage tissues that alleviate water stress under low water availability. The succulent syndrome has evolved convergently in over 80 plant families and is associated with anatomical, physiological and biochemical traits. Despite the alleged importance of ce...
Article
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Succulent plants represent a large functional group of drought-resistant plants which store water in specialized tissues. Several co-adaptive traits accompany water-storage capacity to constitute the succulent syndrome. A widely reported anatomical adaptation of cell walls in succulent tissues allows them to fold in a regular fashion during extende...
Article
Succulence is widely interpreted as an adaptation to drought, usually associated with CAM and xeromorphic features among arid-adapted plants. However, this syndrome can also be observed in species typical of mesic and even hydric environments. The leaf-succulent genus Crassula (Crassulaceae) occurs in contrasting habitats in all nine biomes of sout...
Article
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The genus Aloe is widely used for medicinal purposes throughout its predominantly African distribution, but detailed knowledge of the contemporary value of aloes is patchy. The main aim of this study was to determine the value of Aloe in the Highlands of Ethiopia, a region of rich Aloe diversity, by documenting local uses and perceptions of the sus...
Article
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Bioenergy is a major component of the global transition to renewable energy technologies. The plant and fungal kingdoms offer great potential but remain mostly untapped. Their increased use could contribute to the renewable energy transition and addressing the United Nations Sustainable Development Goal 7 "Ensure access to affordable, reliable, sus...
Book
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Kew’s State of the World’s Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kew’s State of the World’s Plants and Fungi sets an important inte...
Article
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Two new species of Aloe were found in the eastern rainforest of Madagascar during a Kew Madagascar Conservation Centre (KMCC) Team expedition in November 2014. The first species, Aloe vatovavensis is rare in this habitat. The second, Aloe rakotonasoloi, exhibits characters that are intermediate between the features of Aloe s.str. and the related ge...
Preprint
https://authorea.com/users/337132/articles/462777-travel-tales-of-a-worldwide-weed-genomic-signatures-reveal-colonial-trade-routes-and-prior-adaptation-are-key-to-the-success-of-plantago-major
Article
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Arborescent succulent plants are regarded as keystone and indicator species in desert ecosystems due to their large stature and long lifespans. Tree aloes, the genus Aloidendron, are icons of the southern African deserts yet have proved elusive subjects due to the difficulty of obtaining material of known provenance for comparative study. Consequen...
Article
As part of a revised generic classification of Aloe Linnaeus (1753: 319) sensu lato (Grace et al. 2013), Aloidendron (Berger 1905: 56) Klopper & Gideon F.Sm. in Grace et al. (2013: 9) was established to accommodate six tree aloe species that Berger (1905) previously placed in two sections, Aloe sect. Aloidendron Berger (1905: 56) and A. sect. Draco...
Article
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Coevolutionary theory suggests that an arms race between plants and herbivores yields increased plant specialized metabolite diversity and the geographic mosaic theory of coevolution predicts that coevolutionary interactions vary across geographic scales. Consequently, plant specialized metabolite diversity is expected to be highest in coevolutiona...
Article
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Aloe vera gel is a globally popular natural product used for the treatment of skin conditions. Its useful properties are attributed to the presence of bioactive polysaccharides. Nearly 25% of the 600 species in the genus Aloe are used locally in traditional medicine, indicating that the bioactive components in Aloe vera may be common across the gen...
Article
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Plants have evolved a multitude of adaptations to survive extreme conditions. Succulent plants have the capacity to tolerate periodically dry environments, due to their ability to retain water in a specialized tissue, termed hydrenchyma. Cell wall polysaccharides are important components of water storage in hydrenchyma cells. However, the role of t...
Article
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Drought‐tolerant plants are increasingly recognized as a resource to mitigate the consequences of climate change. Succulent plants use stored water to sustain metabolism during regular droughts; succulence is a highly successful adaptation that has evolved in thousands of species throughout the plant kingdom. Desert (xeromorphic) succulent species...
Article
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The genus Aloe (Asphodelaceae) is well known in Tanzania for its medicinal uses, yet its ethnobotany has not previously been systematically studied in the region. To document the indigenous knowledge of Aloe species, data were collected using semi-structured interviews from 180 respondents of different gender and age groups at four study sites in T...
Article
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Aloe (Asphodelaceae) is a typical element of the succulent flora of the eastern Indian Ocean islands of Madagascar, the Mascarene Islands of Mauritius, and Réunion and the Seychelles. In this region, there are 129 native Aloe spp., all of which are endemic. The most recent classification of Aloe in Madagascar, completed by Reynolds in the 1960s, de...
Article
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Background: As the popularity of Aloe vera extracts continues to rise, a desire to fully understand the individual polymer components of the leaf mesophyll, their relation to one another, and the effects they have on the human body are increasing. Polysaccharides present in the leaf mesophyll have been identified as the components responsible for t...
Article
Full-text available
Ethnopharmacological relevance: The discovery of the antimalarial agent artemisinin is considered one of the most significant success stories of ethnopharmacological research in recent times. The isolation of artemisinin was inspired by the use of Artemisia annua in traditional Chinese medicine (TCM) and was awarded a Nobel Prize in 2015. Antimala...
Preprint
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The genus Euphorbia is among the most diverse and species-rich plant genera on Earth, exhibiting a near-cosmopolitan distribution and extraordinary chemical diversity, especially across highly toxic macro-and polycyclic diterpenoids. However, very little is known about drivers and evolutionary origins of chemical diversity within Euphorbia . Here,...
Preprint
Aloe (Asphodelaceae) is a typical element of the succulent flora of the eastern Indian Ocean islands of Madagascar, the Mascarene Islands of Mauritius, and Réunion and the Seychelles. In this region, there are 129 native Aloe spp., all of which are endemic. The most recent classification of Aloe in Madagascar, completed by Reynolds in the 1960s, de...
Article
Full-text available
Madagascar is a major centre of diversity for the leaf-succulent genus Aloe Linnaeus (1753: 319) accounting for roughly a third of Aloe species (Carter et al. 2011). Approximately 128 species and 161 taxa are known from the region and all are restricted to Madagascar (Rakotoarisoa et al. 2014) and/or the nearby Mascarene archipelago. New taxa are d...
Conference Paper
Full-text available
The aloes are a major group of Old World succulents, comprising over 600 taxa in the genera Aloe, Aloiampelos, Aloidendron, Aristaloe, Gonialoe, and Kumara. Together with Astroloba, Gasteria, Haworthia, Haworthiopsis, and Tulista, they comprise a group known collectively as the alooids, after a Dahlgrenian concept, within Xanthorrhoeaceae subfam. A...
Article
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Sustainable harvesting practices are important for conserving plant species and their habitats, but also the livelihoods of those that depend on them. Aloe ferox, a valuable natural resource harvested for its leaves, is the focus of a recent rural development initiative in the Eastern Cape of South Africa. This has the potential to benefit poor res...
Article
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Humans possess the unique ability for cumulative culture [1, 2]. It has been argued that hunter-gatherer's complex social structure [3-9] has facilitated the evolution of cumulative culture by allowing information exchange among large pools of individuals [10-13]. However, empirical evidence for the interaction between social structure and cultural...
Article
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The current decrease of new drugs brought to the market has fostered renewed interest in plant-based drug discovery. Given the alarming rate of biodiversity loss, systematic methodologies in finding new plant-derived drugs are urgently needed. Medicinal uses of plants were proposed as proxy for bioactivity, and phylogenetic patterns in medicinal pl...
Article
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Background: The genus Aloe is renowned for its medicinal and cosmetic properties and long history of use. Sixty-three Aloe species occur in Kenya, of which around 50 % are endemic. Several species of aloes are threatened with extinction and knowledge about their use is of major importance for sound conservation strategies. The main aims of this st...
Article
Full-text available
Ethnopharmacological relevance: The genus Euphorbia (spurges, Euphorbiaceae) is the third largest genus of flowering plants, with almost 2000 species. Its exceptional diversity of growth forms and near-cosmopolitan distribution have attracted human interest since ancient times. For instance in Australia, topical application of latex of Euphorbia p...
Article
Full-text available
Aloe vera supports a substantial global trade yet its wild origins, and explanations for its popularity over 500 related Aloe species in one of the world's largest succulent groups, have remained uncertain. We developed an explicit phylogenetic framework to explore links between the rich traditions of medicinal use and leaf succulence in aloes. The...
Article
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Aloe barbertoniae Pole-Evans, which has previously been included in the synonymy of A. greatheadii Schönland var. davyana (Schönland) Glen & D.S.Hardy, is here reinstated. This species is adapted to the subtropics of northeastern South Africa where it occurs in the Mpumalanga and Limpopo Provinces. It can be distinguished from A. greatheadii var. d...
Article
Full-text available
a) On the basis of phylogenetic studies, changes have been made to the genus concept of Aloe. Three small genera have been circumscribed from species previously included in Aloe: the tree aloes (Aloidendron, 6 taxa), the rambling aloes (Aloiampelos, 10 taxa) and the unusual Cape endemic Kumara plicatilis in a genus of its own. Additionally, four sp...
Article
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The correct names and synonymy for species of Aloe sect. Chortolirion (A.Berger) Boatwr. & J.C.Manning (Asphodelaceae: Alooideae) are provided. This treatment recognises four species in this section, namely A. welwitschii, A. barendii, A. jeppeae and A. subspicata. Aloe subspicata and A. welwitschii are treated as conspecific by some authors.
Article
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A cytogenetic survey of 17 species in the succulent-leaved genus Aloe L. (Xanthorrhoeaceae subfamily Asphodeloideae) in Ethiopia was undertaken towards a more complete genetic characterisation of the genus throughout its distribution in Africa, Arabia and Madagascar. Somatic metaphase chromosomes of all species studied showed the same diploid chrom...
Article
Full-text available
The Horn of Africa is rich in succulent plants, yet the flora in some parts of the region remains under-explored, owing largely to political instability and inaccessibility. The Republic of Djibouti is a relatively small, politically stable country where botanical studies continue to identify new species records and new taxa. Here, we focus on the...
Article
Full-text available
Introduction: The succulent leaf mesophyll in Aloe species supports a burgeoning natural products industry, particularly in Africa. Comparative data necessary to prioritise species with economic potential have been lacking. Objective: To survey leaf mesophyll monosaccharide composition in the genus Aloe using a predictive phylogenetic approach....
Article
Full-text available
The predominantly southern African Xanthorrhoeaceae subfam. Asphodeloideae (Asphodelaceae subfam. Alooideae) has long been regarded as comprising seven so-called alooid genera (Aloe, Astroloba, Chortolirion, Gasteria, Haworthia, Lomatophyllum, Poellnitzia). A reassessment of the classification of the traditionally broadly circumscribed genus Aloe,...
Conference Paper
Full-text available
Background – The Old World genus Aloe L. comprises ± 630 species to which almost 1300 names have been applied. Members of the genus are prominent components of many, mainly arid, African landscapes. Aloes can be found in Africa (the majority of species), the Arabian Peninsula, Socotra, Madagascar and the Mascarene Islands. The berried aloes of the...
Article
Full-text available
The Horn of Africa is rich in succulent plants, yet the flora in some parts of the region remains under-explored, owing largely to political instability and inaccessibility. The Republic of Djibouti is a relatively small, politically stable country where botanical studies continue to identify new species records and new taxa. Here, we focus on the...
Article
Full-text available
Documented Utility and Biocultural Value of Aloe L. (Asphodelaceae): A Review. The genus Aloe L. (Asphodelaceae) comprises 548 accepted species, of which at least one-third are documented as having some utilitarian value. The group is of conservation concern due to habitat loss and being extensively collected from the wild for horticulture and natu...
Article
Full-text available
Aloe graciliflora Groenew., which has previously been included in the synonymy of A. greatheadii Schonland var. davyana (Schonland) Glen & D.S.Hardy, is here reinstated. This species is adapted to the climatic extremes of South Africa’s eastern Highveld where it occurs southward from near Dullstroom to Waterval- Boven and Badplaas, and westward to...
Article
Full-text available
Aloe L. (Xanthorrhoeaceae) is a genus of over 500 species found on the African continent, Arabian Peninsula, Madagascar and eastern Indian Ocean Islands. It is valued by people at many economic scales but verifiable data, with which to quantify the role of Aloe in local livelihoods and commercial trade, are scarce. For a speciose genus of appreciab...
Book
Full-text available
The genus Aloe is arguably one of Africa’s most iconic and valued plant genera. It is immensely popular among succulent plant collectors and horticulturalists, and is also the source of several commercially used natural products. The aloe names book brings together for the first time information on the current taxonomy of each species, the plethora...
Article
Aloe L. (Asphodelaceae) is a monocotyledonous group of considerable popularity among succulent plant collectors and with a long history of medicinal use. It comprises 548 species occurring throughout Africa, the Arabian Peninsula and western Indian Ocean islands. The first comprehensive ethnobotanical study of Aloe (excluding the cultivated A. vera...
Article
Full-text available
Leaf surface morphology was analysed in 32 species representing the maculate species complex (the poorly resolved section Pictae) in the genus Aloe (Xanthorrhoeaceae). Few comparative morphological data are available for the complex. Leaf surface and stomatal characters observed by scanning electron microscopy show taxonomically significant intersp...
Article
Full-text available
6′-Malonylnataloin, a malonylated derivative of the rare anthrone nataloin, is characterised for the first time from Aloe ellenbeckii A. Berger. Anthrone C-glycosides are among a suite of chemical constituents of systematic importance in Aloe. The compound is of interest as a putative phytochemical marker for the east African taxa in the maculate s...
Article
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Aim: To investigate the traditional antidiabetic uses of indigenous or naturalised South African plants using an optimised screening and scoring method. Materials and methods: Eleven plant specieswere screened against Chang liver, 3T3-L1 adipose and C2C12 muscle cells measuring glucose utilisation in all three cell lines and toxicity in the hepatoc...
Article
Full-text available
Ethnopharmacological relevance: The African-Arabian succulent genus Aloe L. (Aloaceae/Asphodelaceae) is represented by approximately 120 infrageneric taxa in southern Africa, including A. ferox Mill., a species long used in commercial natural products. Aims of the study: To assess the documented ethnobotanical knowledge and biocultural value of ut...
Conference Paper
Full-text available
The Millennium Seed Bank Project is an international plant conservation initiative presently focused on the ex situ conservation of endangered, endemic and economic species in the world’s drylands. This paper discusses the process of identifying priorities for seed banking from over 5000 dryland species in Kenya. Local herbarium data were combined...
Chapter
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Healthcare in southern Africa is almost exclusively polarised between Western and traditional African healthcare systems, but a spectrum of healthcare options (e.g. complementary therapists, faith healers) occur between them. Although government health services in the region provide only Western therapy, the majority of people in southern Africa co...
Article
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Bark products are an important source of medicine in South African traditional healthcare. They are difficult or impossible to identify in the dried state in which they are sold, and misidentification or adulteration increasingly affect their appropriate use. Thin Layer Chromatography was investigated for its potential to authenticate medicinal bar...
Article
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This paper reviews progress in establishing the scientific rationale for and safety of traditional medicine use in Africa. Selected plants were screened for antibacterial, antifungal, anthelmintic, anti-amoebic, antischistosomal, antimalarial, anti-inflammatory and antioxidant activity, as well as psychotropic and neurotropic activity using appropr...
Article
Full-text available
The increasing prevalence and distribution of malaria has been attributed to a number of factors, one of them being the emergence and spread of drug resistant parasites. Efforts are now being directed towards the discovery and development of new chemically diverse antimalarial agents. The present study reports on the in vitro antiplasmodial activit...