Royal Botanic Garden Edinburgh Research Articles

Applying the concept of niche breadth to understand urban tree mortality in the UK

Accelerated climate change has raised concerns about heightened vulnerability of urban trees, spurring the need to reevaluate their suitability. The urgency has also driven the widespread application of climatic niche-based models. In particular, the concept of niche breadth (NB), the range of environmental conditions that species can tolerate, is commonly estimated based on species occurrence data over the selected geographic range to predict species response to changing conditions. However, in urban environments where many species are cultivated out of the NB of their natural distributions, additional empirical evidence beyond presence and absence is needed not only to test the true tolerance limits but also to evaluate species' adaptive capacity to future climate. In this research, mortality trends of Acer and Quercus species spanning a 21-year period (2000–2021) from tree inventories of three major UK botanic gardens - the Royal Botanic Gardens, Kew (KEW), Westonbirt, the National Arboretum (WESB), and the Royal Botanic Garden Edinburgh (RBGE) - were analyzed in relation to their NB under long-term drought stress. As a result, Acer species were more responsive to drought and heat stress. For Acer, positioning below the lower limits of the precipitation of warmest quarter led to an increase in the probability of annual mortality by 1.2 and 1.3 % at KEW and RBGE respectively. In addition, the mean cumulative mortality rate increased corresponding to an increase in the number of niche positions below the lower limits of the selected bioclimatic variables. On the other hand, Quercus species in general exhibited comparable resilience regardless of their niche positions. Moreover, Mediterranean oaks were most tolerant, with cumulative mortality rates that were lower than those of native oaks in the UK. These findings further highlight the importance of incorporating ecological performance and recognizing species-specific adaptive strategies in climatic niche modeling.

A Strategy for Building the WFO Plant List

All scientists will face the challenge of explaining what they do to a friend or relative. Fortunately it is easy for us to explain our work. We are building a list of all known plants. Unfortunately this elicits the awkward question: Hasn’t that been done already? Everyone knows that Linnaeus started the naming convention in the 18th century. Surely we would have created a list of species in the intervening 270 years. Alas, there is no single, global species list. In 2022, when the team at the Royal Botanic Garden Edinburgh (RBGE) took on the coordination of the World Flora Online (WFO) Plant List, we considered what we could do differently to save our successors from this awkward dinner party question. The WFO Plant List’s primary purpose is as a structure for the WFO information portal. The portal contains a large amount of information. The list is a simple database of names and their taxonomic statuses. It currently contains 1.52 million names and 440,000 accepted taxa. Because the list has a global scope and includes all vascular plants and bryophytes, it has great potential to be of use outside the WFO portal. Functions might include a: common vocabulary for ecological monitoring networks; drop down list in a garden management system; destination for taxonomic output beyond a monographic paper; bridge from historical, observational studies to contemporary, molecular, phylogenetic research. common vocabulary for ecological monitoring networks; drop down list in a garden management system; destination for taxonomic output beyond a monographic paper; bridge from historical, observational studies to contemporary, molecular, phylogenetic research. In short, the WFO Plant List can be a single, shared lookup table for plant taxa. There are four well known elements of project management: resources, timescale, quality and scope. We have limited control over the first three of these elements. For resources, our institutes have committed a part of our salaried time to facilitate the project but the vast amount of the work has to be done through collaboration with others. We can only inspire people to contribute and this must be done through principles of FAIR (Findable, Accessible, Interoperable and Reusable) data discussed below. There is no natural timescale for our work; we have therefore established a somewhat artificial drum beat of twice-yearly data releases. This enables us to prioritise smaller batches of work. In a list like this, quality is synonymous with accuracy and non-negotiable. If we have an error in our list, it must be corrected. The only element we have full control over is scope. We can choose what is included and what is not. We do this through the design of our data model. The simpler we can make the model, the more complete we can make the list and the easier it will be to improve quality. We only include names that appear effectively/validly published under the International Code of Nomenclature for Algae, Fungi and Plants (ICNAFP). This is an explicit set of rules we can use to enforce data integrity. Unlike the Catalogue of Life, the Global Biodiversity Information Facility (GBIF) or the Global Names Architecture (GNA), we do not have to model names governed by other nomenclatural codes and can focus our resources. From the start, we have separated nomenclature from taxonomy. This gives us a clear set of nomenclatural facts supported by appropriate references that will not change over time, alongside taxonomic opinion that is linked to relevant supporting literature. We only support a single consensus taxonomy but by keeping snapshots of the taxonomy every six months, we allow changes in the science to be tracked through time. The separation of nomenclature from taxonomy within our identifier schema allows third parties to maintain their own classifications whilst mapping to our classification through taxonomically neutral name identifiers. If we had been working a decade or more ago, we would have created tables for ancillary data such as literature, specimens and people. Today we can take advantage of the many data sources available via web links and only store data on nomenclatural acts and taxonomic placement. All other data is represented by a generic referencing mechanism. A reference consists of a URL (including digital object identifiers (DOIs) in URL form) and a citation string. This approach dramatically increases our ability to focus on taxonomic coverage and leaves specialist systems such as International Plant Names Index (IPNI), Biodiversity Heritage Library (BHL) and WikiData to handle other classes of data. More important than the way we model the data is how it is produced and consumed by others. As a node in a graph of linked biodiversity information, our success is measured by the number of links we have to other nodes and people. The data is being produced and maintained by a growing community organised into Taxonomic Expert Networks (TENs). There are about 300 individual scientists in 44 approved TENs. These TENs can contribute to the live dataset via submission of bulk data or by using a dedicated editing platform called Rhakhis. Care is taken to give attribution for contributions at the finest level of granularity possible using Open Researcher Contributor Identifiers (ORCID). We strive to have the data available in bulk and at the level of each name under FAIR principles. All data is released under a Creative Commons CC0 licence. It is made available through the WFO portal, a dedicated API, ChecklistBank and Zenodo on a six-monthly release cycle. The dataset has a citable DOI as well as each version having its own DOI. All names have a stable URI and each version of each taxon has a stable URI. There is a name-to-ID matching service available through the API and as a web interface, and there are two R packages (WorldFlora and wfor) to facilitate analysis workflows.

SHORT NOTE Air layering as a propagation method in glasshouse cultivation

The glasshouse renovation works being undertaken at the Royal Botanic Garden Edinburgh (RBGE) as part of the Edinburgh Biomes Project (2020–2027) pose a number of challenges to the horticulturists managing the plant collections. The grandeur of many of the larger specimens and the limit of available space are the most prominent of these. Air layering is a propagation method that until recently has not been used widely at RBGE. It has however proven to be a successful technique to maintain the genetic diversity of the collection while reducing both the need for space in propagation glasshouses and the level of aftercare required once propagation is complete. This Short Note explains the method used and highlights several successful propagations, illustrated with images, along with suggestions for implementing the method in the future.

(2945) Proposal to reject the name Commelina nimmoniana (Commelinaceae)

(2945) Commelina nimmoniana J. Graham, Cat. Pl. Bombay: 224. Jun–Dec 1839 (Angiosp.: Commelin.), nom. utique rej. prop. Neotypus (vide Nandikar & Gurav in Phytodiversity 2: 81. 2015): India, Maharashtra, Mumbai, Malabar Hill Garden, 28 Sep 2013, Nandikar 1432 (SUK). The name Murdannia semiteres (Dalzell) Santapau (in Poona Agric. Coll. Mag. 41(4): 15. 1951) (Commelinaceae) has long been in near-exclusive use for a well-known species, distributed throughout tropical Asia and Africa. This species was originally described as Aneilema semiteres Dalzell (in Hooker's J. Bot. Kew Gard. Misc. 3: 138. 1851) based on specimens from Konkan, India. It is characterised by fleshy, subulate, semiterete leaves and Santapau (l.c.) transferred it to Murdannia Royle (Ill. Bot. Himal. Mts.: 403. Mar–Apr 1840). Two other species with similar vegetative features were described from India, namely, M. juncoides (Wight) Rao & Kammathy (in Bull. Bot. Surv. India 6: 3. 1965) (≡ Dichoespermum juncoides Wight, Icon. Pl. Ind. Orient.: t. 2078. 1853) and M. sahyadrica Ancy & Nampy (in Willdenowia 42: 79. 2012). Graham (Cat. Pl. Bombay: 224. 1839) described Commelina nimmoniana J. Graham (≡ Murdannia nimmoniana (J. Graham) Bole & M.R. Almeida in J. Bombay Nat. Hist. Soc. 83: 593. 1986 [‘1987’]) with the description “A small plant with discoloured linear pointed leaves.” Original materials of this name are not available, as the author did not cite a type nor could any specimen available to Graham be traced. Brenan (in Kew Bull. 7: 184. 1952) on the basis of the scanty description referred to Graham's name as a “nomen subnudum”. Consequently, POWO (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:172881-1) did not recognize the name Commelina nimmoniana J. Graham (l.c.) as validly published and considered it to have been effectively published (inadvertently) at a later date, citing it as C. nimmoniana J. Graham ex C.B. Clarke in Candolle & Candolle (Monogr. Phan. 3: 191. 1881). The discoloured needle-like leaves, the features given by Graham (l.c.) are equally applicable to three species of Murdannia: M. juncoides, M. sahyadrica, and M. semiteres. Bole & Almeida (l.c.) synonymised M. semiteres (Dalzell) Santapau under M. nimmoniana. Nandikar & Gurav (in Phytodiversity 2: 81. 2015) designated a neotype for the latter name and treated M. juncoides and M. sahyadrica as varieties of it. Nampy & Joby (in Rheedea 18: 57. 2008) discussed the ambiguity concerning the identity of M. juncoides and treated it as distinct from M. semiteres based on its bulbous base, phenology (flower opens in the afternoon) and the seed-testa characteristics. Murdannia sahyadrica is distinguished by its orbicular petals, stamens arranged symmetrically around the central erect style, ovoid capsules and uniseriately arranged seeds. Dalzell's (l.c.) epithet, as Murdannia semiteres (Dalzell) Santapau, has been almost consistently used by subsequent workers in floristic works in parts of Africa, India and South-East Asia. However as neotypified by Nandikar & Gurav (l.c.), the earlier M. nimmoniana, based on Commelina nimmoniana, has priority over M. semiteres. Although Graham (l.c.) provided information on the form of the leaves and the colour of the flowers, this proves insufficient to ascertain Graham's intended identity for the name C. nimmoniana. Accepting M. nimmoniana would disrupt the widely accepted usage of M. semiteres, which appears in checklists and floristics works covering parts of Africa, India and South-East Asia (Malaisse in Troupin, Fl. Rwanda 4: 140. 1988; Karthikeyan & al., Fl. Ind. 2. Monocot.: 29. 1989; Nguyen, Checkl. Pl. Sp. Vietnam 3: 468. 2005; Faden in Fl. Trop. E. Africa, Commelin.: 55. 2012; Ancy & Nampy, Murdannia India: 104. 2015; Anonymous, Fl. Karnataka Checkl. 2: 235. 2019; Britto, Fl. Centr. N. Tamil Nadu 1: 261. 2019; Mao & Dash, Fl. Pl. India Annot. Checkl. Monocot.: 215. 2020; Narasimhan & Irwin, Fl. Pl. Tamil Nadu Compend.: 308. 2021) and online databases such as African Plant Database (https://africanplantdatabase.ch/en/nomen/11801), The Catalogue of Life (http://www.catalogueoflife.org/annual-checklist/2019/details/species/id/01d4fb2360d2d32ab6795076a4e28cc6), Flora of Zambia (https://www.zambiaflora.com/speciesdata/species.php?species_id=225830), GBIF (https://www.gbif.org/species/2764823), and POWO (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:172881-1), all accessed 13 Dec 2022. In this context the only way to avoid this disadvantageous change of name and to ensure nomenclatural stability in the future is to reject Commelina nimmoniana J. Graham and the combination based on it. MKM, https://orcid.org/0000-0002-6975-480X SN, https://orcid.org/0000-0001-5744-7522 The authors thank Dr. John McNeill, Royal Botanic Garden Edinburgh, Scotland, U.K. and Dr. Subir Bandyopadhyay, Kolkata for helpful consultation in preparing this proposal. MKM and SN are thankful to RUSA and SERB for financial assistance.

(2947) Proposal to reject the name Bryophyllum triangulare (Crassulaceae: Kalanchooideae)

(2947) Bryophyllum triangulare Blanco, Fl. Filip., ed. 2: 221. 1845 [Angiosp.: Crassul.], nom. utique rej. prop. Typus: non designatus. In 1869, John Gilbert Baker (1834–1920) was appointed as the first assistant in the Herbarium of the RBG Kew and in this capacity he was provided with large volumes of often undescribed plant material that was collected in various parts of the world, including in Madagascar. Kalanchoe tomentosa Baker (in J. Bot. 20: 110. 1882), inter alia described as “A succulent perennial, densely coated throughout with short brown spreading hairs”, was one of the taxa that Baker (l.c.) described based on material collected in central Madagascar by the Reverend Richard Baron (1847–1907). Thirty-seven years earlier, Francisco Manuel Blanco (1778–1845) published the name Bryophyllum triangulare Blanco (Fl. Filip., ed. 2: 221. 1845) without an indication of the origin of the material. Curiously, Blanco (l.c. 1845) apparently recognised Bryophyllum Salisb. (Parad. Lond.: t. 3. 1805) in preference, rather than in addition, to Kalanchoe Adans. (Fam. Pl. 2: 248. 1763). However, Bryophyllum is at present treated as a subgenus in Kalanchoe, as K. subg. Bryophyllum (Salisb.) Koord. (in Bull. Jard. Bot. Buitenzorg, sér. 3, 1: 170. 1919). Although not mentioning the hairy character of his material, the description of Bryophyllum triangulare provided by Blanco (l.c. 1845) largely coincides with that of material consistently known as K. tomentosa. Blanco (l.c. 1845) inter alia stated: “Hojas sesiles, opuestas, muy carnosas, lanceoladas, y de tres ángulos como de figura de bayoneta, enterisimas. Cal. como en la especie anterior. Cor. muy larga, con cuatro ángulos, y el limbo con cuatro lacinias. […]. Espec. nueva” (Leaves sessile, opposite, very fleshy, lanceolate, with three angles like the shape of a bayonet, entire. Calyx as in the preceding species [Bryophyllum serratum Blanco (l.c. 1845: 220), where the calyx is described as: “Cal. muy corto, hendido muy profundamente en cuatro partes” (Calyx very short, very deeply divided into four parts)]. Corolla very long, with four angles, the limb divided into four lobes. […]. New species). In the first edition of his Flora of the Philippines, Blanco (Fl. Filip.: 382–383. 1837) provided exactly the same description for Cotyledon lanceolata Blanco (l.c. 1837: 382), non Forssk. (Fl. Aegypt.-Arab.: CXI & 89. 1775), with the sole exception that “otros” was given as “otro” in the 1837 work. By not adopting “lanceolata” in the correct form in Bryophyllum when he transferred C. lanceolata Blanco non Forssk. to Bryophyllum, Blanco was likely following the then widely implemented “Kew Rule” that did not require retention of the epithet of the original species name when a species is transferred to a different genus. Although Blanco (l.c. 1837: 382; l.c. 1845: 221) recorded the leaves of the material he described as B. triangulare as “opuestas” (opposite), which is the common condition in Kalanchoe, the leaves of K. tomentosa are alternately arranged, but especially towards a branch apex often appear to be rosulately clustered or even opposite. Just over 20 years before Bryophyllum triangulare was described by Blanco (l.c. 1845), Karl T. Hilsenberg (1802–1824) and Wenceslas Bojer (1795–1856) made the first significant plant collections in the interior of Madagascar, during an 18-month period, from May 1822 until October 1823 (Dorr, Pl. Coll. Madagascar Comoro Isl.: 52–53. 1997; Figueiredo & Smith in Phytotaxa 568: 185. 2022). Material collected in Madagascar was therefore increasingly being distributed, and evidently had also reached Blanco in the Philippines, with Merrill (Sp. Blancoan.: 161. 1918, Enum. Philipp. Fl. Pl. 2: 217. 1923) later noting that the species was in cultivation. Hamet (in Bull. Herb. Boissier, sér. 2, 7: 899. 1907) included Bryophyllum triangulare, as “B. triangulore”, in the synonymy of a very broadly conceived Kalanchoe laciniata (L.) DC. (Pl. Hist. Succ.: t. 100. 1802). This was in contrast to Merrill (Rev. Blancos Fl. Filip.: 43. 1905) who, likely following Fernández-Villar (Nov. App.: 78. 1880), rather associated the name B. triangulare with K. spathulata DC. (Pl. Hist. Succ.: t. 65. 1801). However, Merrill (l.c. 1918; l.c. 1923) later agreed with Hamet (l.c. 1907) and rather placed the name B. triangulare in the synonymy of K. laciniata. Although a variable species as circumscribed at present, none of the variants of K. laciniata and K. spathulata has leaves that are “very fleshy, lanceolate, with three angles like the shape of a bayonet”, as described by Blanco, who left no herbarium, for B. triangulare, so it would seem inappropriate to neotypify Blanco's name on either of the “illustrative specimens” that Merrill (l.c. 1918) associated with these other names. Rather, B. triangulare was the first description of K. tomentosa, and its treatment as a heterotypic synonym of the latter has been suggested (e.g., https://wfoplantlist.org/plant-list/taxon/wfo-0001299811-2022-12), despite the epithet “triangulare” having to be combined with Kalanchoe, in accordance with Art. 11.4 of the ICN (Turland & al. in Regnum Veg. 159. 2018). The name Kalanchoe tomentosa is consistently in use in works on the taxonomy of Kalanchoe (e.g., Baillon in Bull. Mens. Soc. Linn. Paris 1: 468. 1885; Hamet in Bull. Herb. Boissier, sér. 2, 8: 31. 1908; Raymond-Hamet & Perrier de la Bâthie in Ann. Mus. Colon. Marseille, sér. 3, 3: 102. 1915; Raymond-Hamet & Marnier-Lapostolle in Arch. Mus. Natl. Hist. Nat., sér. 7, 8: 37. 1964; Maire, Fl. Afrique N. 14: 253. 1977; Boiteau & Allorge-Boiteau, Kalanchoe Madagascar: 166. 1995; Descoings in Eggli, Ill. Handb. Succ. Pl. Crassulaceae: 178. 2003; Smith & al., Kalanchoe S. Africa: 299. 2019), as well as for material widely available in the horticultural trade (Jacobsen, Lex. Succ. Pl., ed. 2: 290. 1977; Jacobsen, Handb. Succ. Pl. 2: 631. 1986; Rauh, Succ. Xerophyt. Pl. Madagascar. 1: 92, 93. 1995; Brickell, RHS A–Z Encycl. Gard. Pl., corr. repr.: 578. 1998; Brickell, RHS A–Z Encycl. Gard. Pl., ed. 2, 2: 594. 2003; Bryant & al., Ultimate Pl. Book: 741. 2005). The name K. tomentosa is also in use in the African Plant Database (https://africanplantdatabase.ch/en/nomen/210198), which includes the Catalogue of the Vascular Plants of Madagascar. For over 110 years, the name Bryophyllum triangulare has not featured in any works on Kalanchoe and rejecting it will have no negative nomenclatural effect. Therefore, to avoid a disadvantageous name change and future redundant nomenclatural discussions, the rejection of the name B. triangulare is here proposed, in accordance with Art. 56. GFS, https://orcid.org/0000-0002-5417-9208 Prof. John McNeill, Royal Botanic Garden Edinburgh, U.K., and Dr John Wiersema, Department of Botany, Smithsonian Institution, Washington, D.C., U.S.A., are thanked for kindly commenting on this issue.

Rediscovery of an ancient herbarium for Turkish botanical history: Bolu Girls Village Institute Herbarium

Bolu Girls’ Village Institute Herbarium (Bolu Kız Köy Enstitüsü Herbaryumu) was founded in 1953 by Muhittin Fehmi Özgen. It is one of the earliest herbaria of the Turkish Republic. The herbarium was part of the natural history collections of the school which also included insects, minerals, and fossils. The herbarium initially contained around 2500 specimens within 72 cardboard boxes. Additionally, specimens from this herbarium were sent to İstanbul University Department of Biology Herbarium (ISTF) and around 600 specimens to the herbarium of Royal Botanic Garden Edinburgh (E). In 2006, we received 567 plant specimens in five boxes. The plants were mainly collected from Bolu and neighboring provinces between 1953 and 1958. The herbarium collection contains one bryophyte specimen and three seedless vascular plants. The remaining taxa belong to gymnosperms and angiosperms. The herbarium labels were prepared both in Latin and Turkish. Majority of the specimens have identification up to family and genus level and a small number of them up to species level. This herbarium remained largely unknown to Turkish botanists. Therefore, we think it is valuable to provide detailed information about the history and the content of the herbarium. The information given here not only will contribute to our knowledge about the natural history collections of Turkey but also to the education history of the Turkish Republic.

A research agenda for nonvascular photoautotrophs under climate change.

Nonvascular photoautotrophs (NVP), including bryophytes, lichens, terrestrial algae, and cyanobacteria, are increasingly recognized as being essential to ecosystem functioning in many regions of the world. Current research suggests that climate change may pose a substantial threat to NVP, but the extent to which this will affect the associated ecosystem functions and services is highly uncertain. Here, we propose a research agenda to address this urgent question, focusing on physiological and ecological processes that link NVP to ecosystem functions while also taking into account the substantial taxonomic diversity across multiple ecosystem types. Accordingly, we developed a new categorization scheme, based on microclimatic gradients, which simplifies the high physiological and morphological diversity of NVP and world-wide distribution with respect to several broad habitat types. We found that habitat-specific ecosystem functions of NVP will likely be substantially affected by climate change, and more quantitative process understanding is required on (1) potential for acclimation, (2) response to elevated CO2 , (3) role of the microbiome, and (4) feedback to (micro)climate. We suggest an integrative approach of innovative, multimethod laboratory and field experiments and ecophysiological modelling, for which sustained scientific collaboration on NVP research will be essential.

Digitisation of the Natural History Museum's collection of Dalbergia, Pterocarpus and the subtribe Phaseolinae (Fabaceae, Faboideae).

In 2018, the Natural History Museum (NHMUK, herbarium code: BM) undertook a pilot digitisation project together with the Royal Botanic Gardens Kew (project Lead) and the Royal Botanic Garden Edinburgh to collectively digitise non-type herbarium material of the subtribe Phaseolinae and the genera Dalbergia L.f. and Pterocarpus Jacq. (rosewoods and padauk), all from the economically important family of legumes (Leguminosae or Fabaceae).These taxonomic groups were chosen to provide specimen data for two potential use cases: 1) to support the development of dry beans as a sustainable and resilient crop; 2) to aid conservation and sustainable use of rosewoods and padauk. Collectively, these use case studies support the aims of the UK's Department for Environment Food & Rural Affairs (DEFRA)-allocated, Official Development Assistance (ODA) funding. We present the images and metadata for 11,222 NHMUK specimens. The metadata includes label transcription and georeferencing, along with summary data on geographic, taxonomic, collector and temporal coverage. We also provide timings and the methodology for our transcription and georeferencing protocols. Approximately 35% of specimens digitised were collected in ODA-listed countries, in tropical Africa, but also in South East Asia and South America.

Rhakhis: A workflow for managing the WFO taxonomic backbone

In 2021, the World Flora Online (WFO) Council agreed that the team at the Royal Botanic Garden Edinburgh would take on the technical role of managing the WFO Taxonomic Backbone (WFO-TB). This presentation outlines the implementation of a system to manage the associated data and explores possible future developments. The WFO-TB is a global concensus checklist of plants including bryophytes, pteridophytes, gymnosperms and angiosperms. The checklist data consists of two parts: facts concerning the nomenclatural acts that establish the names under the nomenclatural code, and consensus expert opinion on the placement of those names into a single, authoritative taxonomy. WFO-TB is unique in that it is both global in scope and curated by a large team of experts from multiple institutions. There are currently around 280 specialist contributors organised into 37 Taxonomic Expert Networks (TENs). The primary function of the WFO-TB is to provide structure to the hundreds of thousands of descriptions, images and other pieces of Content that make up the WFO’s main web portal, but periodic snapshots of the taxonomic data are also made available as public downloads and published as the WFO Plant List. The WFO Plant List is unique in that it remembers each version of WFO-TB that was published and links between them thus providing a stable, citable resource. In addition, data can be released in any format that researchers may find useful including through ChecklistBank and so be potentially incorporated into the Catalogue of Life and GBIF (Global Biodiversity Information Facility). All checklist data are released with a Creative Commons (CC) license of CC0 so that others may freely build upon, enhance and reuse the works for any purposes without restriction under copyright or database law. Prior to 2022, the WFO-TB was managed as part of the main WFO data resources supporting the WFO Portal by the team at Missouri Botanical Garden. Moving responsibility for hosting the backbone to the team at Edinburgh added significant resources to the project as a whole, but created technical challenges. The first requirement of the new system (called Rhakhis, a Greek form of rachis, the ‘backbone’ of a leaf or inflorescence) was to demonstrate that it could feed data back to Missouri in a way that could be incorporated into the WFO infrastructure without causing disruption to the Content curation process. This was completed in early 2022, and, by June, the primary copy of the WFO-TB data had been entrusted to Rhakhis. The June 2022 version of the WFO Plant List and the WFO-TB was published using the previous system, switching to publication from Rhakhis in December 2022. The system architecture of Rhakhis is quite simple. A MySQL database holds all the data and is exposed via a GraphQL API to a web-based user interface written in Javascript using React and Bootstrap. User authentication is handled via a link to ORCiD (Open Researcher and Contributor ID). Authorisation for editors is delegated hierarchically down the taxonomic tree. This provides the ability for TENs and the TEN Manager to oversee and manage the live data directly and to delegate authority to colleagues. The TEN Manager has access to a plain HTML bulk loader interface that enables the ingestion of CSV and files in DwC-A (Darwin Core Archive) format supplied by TENs as well as updates from other data sources, such as IPNI (International Plant Names Index) and WCVP (RBG Kew’s World Checklist of Vascular Plants). Rhakhis is designed as a standalone data management tool for taxonomists involved in the project rather than a public website, and is hosted on a WFO server on the Google Cloud. The WFO Plant List is run on a separate system and designed to be a performant public-facing website. Periodic snapshots of the WFO-TB are imported into a Solr Index that is then exposed via another GraphQL API as well as Semantic Web-compliant HTTPS URIs. A web-based user interface to WFO Plant List is implemented as part of the Craft CMS (Content Management System) that also runs the About pages of the WFO Web Portal, but it would be possible to build other interfaces to this data. The periodic snapshots of the WFO-TB, which are published through the WFO Plant List, are archived in Zenodo and assigned a DOI (Digital Object Identifier), as well as contributed to Catalogue of Life ChecklistBank. The archive formats currently supported include: Darwin Core Archive and Catalogue of Life Data Package, but other formats will be considered in the future. We are interested in investigating the creation of data papers, e.g., through the Biodiversity Data Journal at Pensoft, to provide additional accreditation for contributors and exposure of their data.

STUDENT PROJECT Missing Maddenia: A review of Rhododendron subsection Maddenia at Logan Botanic Garden

Rhododendron subsection Maddenia has long been cultivated at Logan Botanic Garden, an outpost of the Royal Botanic Garden, Edinburgh (RBGE). It is noted in RBGE’s Collection Policy as one of Logan’s representation themes. Half of RBGE’s Maddenia accessions grow there outdoors in the relatively mild climate that suits these tender plants. It was known that Logan’s collection did not represent the entire Subsection. Therefore, this study’s aim was to investigate how completion might be achieved. Existing literature and known specialists were consulted to compile a list of taxa, although this remains unresolved. Using RBGE’s BG-BASE data and an observational survey of Logan’s living collection, it is suggested that 24 taxa may be absent from the collection. Their native occurrence, ex-situ cultivation and IUCN Red List criteria were researched. Using this information, a simple value system was created in order to prioritise acquisitions that might best serve conservation. This article is abridged and revised from the author’s specialist project, completed in candidature for the HND Horticulture with Plantsmanship.

SHORT NOTE Propagation of Bambusa vulgaris: a simplified method for use in display glasshouses

Horticulture staff at the Royal Botanic Garden Edinburgh have experimented with the propagation of Bambusa vulgaris by planting pieces of stem directly into the bed in which the plant is to grow. The success of the method means that both transportation time and space are saved by removing the stage where these large propagules are in the propagation unit.

Reducing Environmental Impacts at the Royal Botanic Garden Edinburgh

The Royal Botanic Garden Edinburgh (RBGE) has put the climate emergency and biodiversity crisis at the centre of its organisational strategy and is making changes to reduce the environmental impact of its activities and to adapt to the conditions created by changes in climate. This article looks at actions towards the Sustainable Development Goals (SDGs) within the physical boundaries of the four gardens of RBGE in Scotland. The article considers two areas. Firstly, the Horticultural sphere, including the reduction of the impacts on the environment made by horticultural practice to maintain the gardens, and adaptation of the landscapes to improve visitor access and the biodiversity benefits of plantings. Secondly, influencing behaviour and engaging visitors with respect to growing food and the enjoyment of being with plants for health and wellbeing. In both these areas, RBGE activities are contributing to targets within SDGs 11, 12, 13 and 15. These targets, the actions to realise them and subsequent outcomes are described below. Finally, a major project underway at the Garden which will significantly reduce the environmental impacts of the institution, the Edinburgh Biomes, is introduced.

Sibbaldia procumbens: An icon redrawn

A new cover has been created for Sibbaldia the International Journal of Botanic Garden Horticulture to commemorate the 350 Anniversary of the Royal Botanic Garden Edinburgh (RBGE) in 2020. The Sibbald Trust, which supports the work of the Garden, agreed to fund the commissioning of a botanical drawing of the alpine species Sibbaldia procumbens L. to be used as the cover image for volume 20 and subsequent volumes. The drawing and accompanying colour wash overlay will become part of the RBGE Florilegium - a collection of botanical drawings that form a visual record of the Living Collection and a reflection of the scientific and horticultural interests of the institute. This article describes the process of creating a painting of a small plant with minute details. Colour images of the plant and the drawings are also reproduced.

Foreword

The Foreword is written by Simon Milne MBE FRSE, Regius Keeper of the Royal Botanic Garden Edinburgh. He introduces this special edition of Sibbaldia that documents the proceedings of The Sibbaldia & PlantNetwork Conference 2020. The Conference was a major event in the celebration of the 350th anniversary of the Royal Botanic Garden Edinburgh (RBGE), with the primary aim of promoting excellence in botanic garden horticulture. That aim was most certainly achieved thanks to the impressive line-up of speakers and their expertise, combined with the enthusiasm and interaction of all participants. The Conference was held online due to the restrictions of the COVID-19 pandemic, and whilst in-person contact was absent, the virtual format enabled a broader range of delegates to attend.A total of 250 delegates gathered in their virtual space from 28 to 30 October to hear from ten keynote speakers in the main sessions, seven presenters in two parallel sessions and a broad range of expert practitioners in the free session, and for the grand finale – ‘Horticulture in 2020’. The themes ranged from conservation, curation and cultivation to heritage, plant health and education. The insightful papers contained within this volume artfully weave together these themes, reflecting their connectivity. The depth of botanical, horticultural and pedagogical experience is outstanding, the content of the papers reflecting the authors’ vast experience and knowledge.

Garden Profile: The Royal Botanic Garden Edinburgh at 350

The Royal Botanic Garden Edinburgh (RBGE) was founded in 1670 and celebrated its 350th anniversary in 2020. In Edinburgh, Scotland, the institution has occupied four different sites in that time and has been at the current site in Inverleith since 1823. Three other gardens in Scotland are also part of RBGE: Dawyck in Peebleshire, Benmore in Argyllshire and Logan in Dumfries & Galloway. 13,750 species from 2721 genera representing 344 families are cultivated in these four gardens and this article describes some of these collections. It also describes the issues facing the Garden today in common with many large and botanic gardens, those of plant health, implementing environmentally sustainable working practices, and managing collections in the face of a changing climate and growing visitor numbers. The Garden is also planning an exciting future with ambitious plans for new buildings and the refurbishment of historical structures to not only improve plant cultivation facilities, but also to increase visitor engagement and education about the value of plants for a healthy future.

Managing botanic garden collections of high conservation value

The author has spent 30 years co-ordinating the International Conifer Conservation Programme (ICCP), based at the Royal Botanic Garden Edinburgh, and uses this significant milestone to reflect on some important aspects of managing genetic resources in plants of conservation concern. The main driver of the ex-situ component of the ICCP has been to develop robust protocols for broadening the genetic base of threatened conifers and a range of conservation dependent Chilean woody plants in cultivation. This is achieved using well-documented known wild origin material distributed through a dedicated network of ‘safe sites’. Examples of threatened species for which collection and cultivation of a breadth of genetic material has enabled meaningful conservation are given here. The strategy to increase genetic material in cultivation sometimes involves using novel methods including conservation hedges. The great challenge facing all managers of botanical collections is how to develop effective programmes that integrate ex-situ with in-situ conservation. The biggest contribution collection managers and growers can make is to maximise the value of collections in their care and actions which achieve this are listed.

Student Project Deaccessioning: A curatorial review

Deaccessioning in collections can be controversial because of the value associated with some taxa and their conservational, historical, educational, display and research significance within the collection. Twenty-one horticultural institutions completed a survey on the protocols for deaccessioning plant material. The resulting data were collated to provide a comparison of the different approaches institutions take towards deaccessioning their collections. This study has identified that conservation and education are the most important factors in managing garden collections. Accession data of high quality is an essential part of managing a collection, but poor accession data should not be a reason to deaccession plants. Space constraints are the primary factor behind the deaccessioning of collections. This paper is a summary of the research project completed by the author for the BSc in Horticulture with Plantsmanship at the Royal Botanic Garden Edinburgh (RBGE).

Figs S1-S3 & Tables S1-S2

Fig. S1. Rhizophagus intraradices: culturing history of the type and successful ex-type culture attempts (ATT 4) and a new isolate (ATT 1102) from the type location established approx. 30 years later. Both pot cultures (PC) and root organ cultures (ROC) are shown with dates of establishment and voucher numbers for samples that yielded specimens for preservation in herbaria. Sun bags are item B7062, Sigma Aldrich (https://www.sigmaaldrich.com). Location of cultures: Forestry Commission Northern Research Station or other localities in UK; Université catholique de Louvain (UCL); Ludwig Maximilian University of Munich (LMU). Gel refers to a small portion of substrate from a parent ROC, with a single spore, several spores, or root fragments (usually with attached mycelium).Fig. S2. Phylogenetic maximum likelihood phylogenetic tree of Rhizophagus species and isolates characterised for the SSU-ITS-LSU rDNA region, with Sclerocystis as outgroup. Bootstrap (BS) values below 60 % and BS values of terminal sister relations are not shown. “Rhizoglomus venetianum” (= R. irregularis) sequences are marked in red, sequence variants characterised in a Rhizophagus irregularis genome project are marked in blue. Sequences of Rhizophagus intraradices cultures derived from the ex-type culture FL 208, including the epitype (voucher W 5719 from MUCL 52327 = ATT 4-83), are shown in green and sequences of the new isolate collected from the type locality (MUCL 49410 = ATT 1102-12) in brown.Table S1. Rhizophagus intraradices: lengths and widths (µm) of extra- and intraradical spores from two strains, ATT 4 and ATT 1102 spores with inferential statistics (number of spores observed (n), minimum value (Min), first quartile of the data (Q1), median, third quartile of data (Q3), maximum value (Max), mean, standard deviation (SD) and % coefficient of variation (CV %)). Table S2. Rhizophagus intraradices: spore colours from two strains (ATT 4 – type and ex-type) and ATT 1102 (new culture from type locality) from pot cultures (PC) and root organ cultures (ROC). Where possible, colours were matched with charts from Royal Botanic Garden Edinburgh, Munsell, or Methuen Handbook of Colour.

Hydrological and planting design of an experimental raingarden at the Royal Botanic Garden Edinburgh

A new experimental raingarden has been created at the Royal Botanic Garden Edinburgh (RBGE) to help cope with the impacts of more frequent and intense rainfall events. Raingardens offer a sustainable, nature-based solution to flood mitigation by mimicking natural rainwater retention and infiltration characteristics within a constructed bioretention system. By incorporating specially selected plants that can withstand both very wet and very dry conditions, raingardens also provide enhanced biodiversity capacity.
 
 
 This paper reports on the hydrological design of the raingarden, which is aimed at reducing the occurrence of waterlogging and localised flooding within RBGE, before discussing the selection and cultivation of the planting. It is hoped that the mix of plants chosen will encourage a great diversity of wildlife, providing nectar sources for insects and bees in summer, and homes for invertebrates and food for seed-eating birds in winter. With the raingarden having been in place for over a year at the time of writing, reflections on its maintenance and
 upkeep during that time and performance assessment for significant storm events will also be discussed.
 

Recreation of the Edinburgh Potato Solanum ×Edinense Berthault

Solanum ×edinense Berthault, is a spontaneously occurring hybrid between S. demissum Lindl. and the cultivated potato, S. tuberosum L., found near potato fields in Mexico. Although not described until 1911, this hybrid was in cultivation at the Royal Botanic Garden Edinburgh shortly after the Irish Potato Famine of 1845–1849 and proved to be highly resistant to late blight, Phytophthora infestans. In the mid-19th century late blight caused widespread failure of the potato crop across Europe and played a central role in the Irish Potato Famine. Using the parent species in controlled crosses we have recreated the hybrid that was named by Berthault in recognition of the Royal Botanic Garden Edinburgh as the source of his plant material. We have also researched the early history of this hybrid potato in Edinburgh and demonstrated disease resistance through field exposure during the outbreak of late blight in Edinburgh in 2019. This work underlines the important role of this hybrid in the breeding of disease resistant potato cultivars.