Constancea 83, 2002
University and Jepson Herbaria
P.C. Silva Festschrift

Marine Algal (Seaweed) Collections at the Natural History Museum, London (BM):
Past, Present and Future

Ian Tittley
Department of Botany,
The Natural History Museum,
London SW7 5BD


The specimen collections and libraries of the Natural History Museum (BM) constitute an important reference centre for macro marine algae (brown, green and red generally known as seaweeds). The first collections of algae were made in the sixteenth and seventeenth centuries and are among the earliest collections in the museum from Britain and abroad. Many collectors have contributed directly or indirectly to the development and growth of the seaweed collection and these are listed in an appendix to this paper. The taxonomic and geographical range of the collection is broad and a significant amount of information is associated with it. As access to this information is not always straightforward, a start has been made to improve this through specimen databases and image collections. A collection review has improved the availability of geographical information; lists of countries for a given species and lists of species for a given country will soon be available, while for Great Britain and Ireland geographical data from specimens have been collated to create species distribution maps. This paper considers issues affecting future development of the seaweed collection at the Natural History Museum, the importance and potential of the UK collection as a resource of national biodiversity information, and participation in a global network of collections.


In the eighty years of Paul Silva's life the approaches to development and growth of Museum collections have changed considerably. No longer are they an indicator of the wealth and importance of the owner but are now considered part of a shared global resource. There is a responsibility recognised by collection managers not only to care for and maintain their collections but also to make them accessible and available. At the start of Paul Silva's career the cataloguing of collections was considered to be at best a laborious task and at worst an impractical task. Paul is one of the few to have successfully undertaken the manual organisation of large amounts of complex algal nomenclatural and taxonomic information. The many publications by Paul Silva dealing with such matters (as demonstrated in the recently published Catalogue of the benthic marine algae of the Indian Ocean, Silva et al. 1996) have created tools vital to the organisation of a large collection of algae and its associated information. The importance of specimen collections, their care and maintenance into the future, is implicit in his studies.

Paul visited the Natural History Museum (BM) on several occasions and studied its collections. However, it came as a surprise that his name was not in the list of collectors listed in the Appendix (Table 1) and that no material of his is held. We would welcome any duplicate specimens of his that may be available! In the early 1950s Paul comprehensively revised the collections of Codium at BM. A typical specimen studied and annotated by him is shown in Figure 1; not surprisingly he set an excellent example in being one of only a few workers who annotated every specimen studied with a comment as to its determination.

This paper, dedicated to Paul Silva, considers briefly the seaweed collection at BM, its growth and development from past, present and future perspectives, and its relevance to contemporary issues.


Floristic studies and research into problems in systematics and taxonomy have been the driving forces for the growth and development of the marine macro-algal (seaweed) collection at the Natural History Museum (BM). Algal collections held in museums, marine laboratories and universities form a large information resource. It is not possible to quantify the global size of this resource but BM holds approximately 350000 specimens of world-wide origin and this probably represents a significant proportion of the global resource of seaweed specimens.

Since the amalgamation of the cryptogamic collections of the Royal Botanic Gardens Kew with those of the Natural History Museum there has been an increasing demand for information on the marine algal collection now housed at BM. Only scant published information deals with the latter; Lankester (1904), Newton (1952) and Dickinson (1952) provided brief lists of collectors and collections while Koster (1962) collated some data on types. Stearn (1981) briefly mentioned marine algal collections in his history of the Natural History Museum, London. Tittley (1974) described the collection and activities of a nineteenth century phycologist (T.H. Buffham) who made a significant contribution to the development of the BM collection and to phycological knowledge and research at that time. The rapid advance of information technology and computing in the 1980s and 1990s facilitated access to collection information through construction of specimen databases and cataloguing projects that would have been difficult to complete using manual facilities. A start was made at BM in the 1980s to provide electronically collated information on type and historically important specimens (Tittley and Tyler 1983; Tittley et al. 1984, 1985, 1989). An innovative feature at that time was the preparation of geographical indexes to the collection (Tittley and Sutton, 1984; Tittley et al. 1984, 1985, 1989) of value in floristic and biogeographical studies.

An under-rated value of preserved collections is that they are verifiable records of an alga's existence in time as well as space (Huxley and Bryant 1999). Collections and the associated data may therefore contribute to the recognition of change or stability, temporal and spatial occurrence, changes in alpha diversity, and environmental change. The use and value of herbarium and other specimens and associated data in environmental (Brooke, 2000a; Cranbrook 1997; Gellini and Paoletti 1993; Huxley and Bryant 1999; Tittley 1977, 2001a, b) and conservation (Snow and Keating 1999) studies is beginning to attract greater recognition. There will be an important role for museums in housing and maintaining selected voucher specimens. The role of marine sample collections generally, their value, use, and future has also recently been the subject of a review and forward look (Rothwell 2001; Tittley 2001b for algae).


The earliest collections

The Sloane Herbarium at BM is probably the most extensive early assemblage of botanical collections made largely in the seventeenth and eighteenth centuries and includes many specimens of algae; it probably represents the beginning of marine algal (seaweed) study (Murray 1895). Dandy (1958) compiled an annotated list of the component collections and information on the contributors; algal specimens in the Sloane Herbarium originate from Britain and overseas. There are also some early specimens in the main marine algal herbarium. These early algal collections are not only important for nomenclatural and taxonomic research but also provide a historical insight into the marine flora of the past. The type of Sphaerococcus coronopifolius Stackhouse is a specimen in the Sloane Herbarium from Cornwall (volume HS 114 folio 12), and the lectotype of Phyllophora pseudoceranoides (S.Gmelin) Newroth & A.R.A.Taylor (Figure 2) is based on a specimen probably from Dover in the Buddle Collection of the Sloane Herbarium (HS 114 f. 27). The occurrence of Padina pavonica (Linnaeus) Thivy at Harwich on the east-coast of England is confirmed by a specimen in the Sloane Herbarium (HS 114 f. 26; Figure 3). The location is beyond its present northern limit of distribution and analysis of past specimen and literature records of P. pavonia led Price et. al. (1979) to conclude that a contraction in range had occurred during past centuries.

Price and Tittley (1972) observed that specimen and literature records of marine algae from the county of Kent in England are among the earliest for the British Isles and probably for the world. Although the Sloane Herbarium contains relatively few localised British specimens, many of those that are localised originate from Kent. The Sloane and main algal herbaria contain 24 species from Deal, Dover, Sheerness, and the Isle of Sheppey. Irrespective of whether or not material was collected as attached specimens or from the drift, most of the species preserved in the collections can be found on the Kent coast today. Fucus serratus Linnaeus, F. vesiculosus Linnaeus, Halidrys siliquosa (Linnaeus) Lyngbye, Laminaria digitata (Hudson) Lamouroux and Ulva lactuca Linnaeus characterise the littoral rocky shore biotopes of the Kent coast. Ceramium nodulosum (Lightfoot) Ducluzeau, Chondrus crispus Stackhouse, Enteromorpha prolifera (O.F.Müller) J.Agardh, Furcellaria lumbricalis (Hudson) Lamouroux, Halurus flosculosus (Ellis) Maggs & Hommersand, Membranoptera alata (Hudson) Stackhouse, Osmundea pinnatifida (Hudson) Stackhouse, Phyllophora pseudoceranoides (Figure 2), Plumaria plumosa (Hudson) Kuntze, Polyides rotundus (Hudson) Greville, and Porphyra purpurea (Roth) C.Agardh are common understorey species on the rocky shores of Kent. The foliose red alga Calliblepharis ciliata (Hudson) Kützing is a common sublittoral species and drift specimens occur frequently. Specimens of Ascophyllum nodosum (Linnaeus) Le Jolis and Polysiphonia lanosa (Linnaeus) Tandy collected from Deal in 1698/9 were undoubtedly drift and probably originated from the Lower Greensand rock outcrop at Folkestone (20 km to the west) where both grow today. A Halopitys incurvus (Hudson) Batters specimen was probably also drift as the species does not occur in Kent. The status of a Jania rubens (Linnaeus) Lamouroux specimen is interesting as there is evidence to suggest that this species has become extinct in the southern North Sea (Scott and Tittley 1999). The Sloane Herbarium also contains specimens of marine species in the past confused with algae; these include the intertidal sea-grass Zostera angustifolia (Hornemann) Reichenbach (from the Isle of Sheppey close to where it now occurs), ‘Silken Wrack’ (Flustra foliacea Linnaeus 1758) and Fucus spongiosus nodosus (Alcyonium digitatum (Linnaeus 1758)). The last two are species of fauna that characterise sublittoral biotopes on the north coast of Kent and are commonly found as drift.

Later seaweed collectors and collections

Most of the 350000 specimens at BM are dried, pressed, herbarium preparations but there are also approximately 20000 microscope slides, 2000 specimens preserved in formalin, and 2000 specimens air-dried and housed in boxes. Most herbarium specimens are mounted on uniform herbarium sheets; some are in bound volumes. The majority of the seaweed collection has been assembled over the past 200 years with a peak of specimen acquisition in the 19th century (a typical specimen of this period is shown in Figure 4).

The collection at BM has developed eclectically reflecting the research interests of staff, the scientific community of the time, and the economic and political activities of Britain. This led for example to the acquisition in the nineteenth century of extensive algal collections from Australia, New Zealand, and parts of North and South America that are rich in type specimens and specimens of historical interest. The collection from Great Britain and Ireland is comprehensive, largely as a result of the flowering of natural history activity involving collecting and taxonomic research, in the nineteenth century.

An important point in the history of the development of the BM algal collection was the amalgamation in 1970 of the BM and Kew (K) collections at BM. This doubled the size of the collections, the number of type and historically important specimens, and as a consequence increased requests for information and loan of specimens. Growth of the BM collection in the twentieth century has otherwise been slower than in the nineteenth century despite increased research activity locally and globally.

Table 1 in the Appendix lists the collectors who have contributed to the growth and development of the BM marine algal collection. It also provides information on the geographical origin of collections and the collection to which the collector has contributed. Over 1000 major and minor individual collectors and 77 titled or published sets of specimens are listed. Although incomplete, the list provides an overview of the components of the BM marine algal collection and those of importance for taxonomic, floristic and other research will be recognised. Not listed are several significant herbaria acquired by the museum the former owner of which was not the collector (e.g., Shuttleworth's Herbarium). Table 1 was compiled in part from manuscript indexes held in the algal herbarium; these also contain additional information on the collectors, content of their collections, and include their whereabouts when not at BM. In some cases there is also biographical information on a collector. Other information was retrieved from computer databases. Full information on algal collectors will become available when all specimens have been registered. A comprehensive database of collectors for all plant groups at BM is also in preparation and will be available via the world-wide-web (Sutton, in prep.).


Specimen registration and information

Until recently, the Botany Department of the Natural History Museum did not register individual incoming specimens; only the main details of a collections or presentation were recorded. Museum policy now requires collections to be accessioned electronically and additional resources have been made available to achieve this. The availability of desk-top computers in the early 1980s catalysed the initiation of specimen databases. The improvement of computer hardware and software now allows us to undertake tasks that would have been impossible before the 1980s and to plan a management strategy for doing these. The first attempts at creating specimen databases targetted information associated with type and historically important specimens (e.g., Tittley and Tyler, 1983) and our current approach will continue with this. However, in contrast to the previous computer-based cataloguing, all specimens are now registered with a unique identifier represented by a bar-coded numbered label (see Figure 4). Also, images of specimens (figures in this paper) can now be captured using a flat-bed scanner or a digital camera. An important point for users is that the bar-code number provides a unique reference to a specimen and this should always be cited when referring to specimens in reports and publications. Although the databases are as accurate as possible they are subject to caveats including correct label interpretation and specimen determination (see Tittley 1985).

The present strategy for specimen registration of the seaweed collection is:

  1. To review the status of all specimens in the collection, identify type and historically important specimens, register each specimen with a unique (bar-code) number (see Figure 4), enter all associated information into a database and prepare digital images of type specimens.

    This has been completed for the Phaeophyta with 1297 specimens registered and images prepared. 1777 specimens of Rhodophyta (A to Gigartina) have been registered and information incorporated into a database; 647 specimens of Chlorophyta have been provisionally identified as of possible type or historically important status.

  2. To register each specimen received with a bar-code number and enter all information associated with the specimen into a database.
  3. To target selected parts of collection for registration and collation of associated information.

    Projects under way or completed include: the ‘Schmitz collection’ of microscope slides (see Bryant and Irvine 2002), the ‘Batters collection’ of microscope slides (completed), the general collection of microscope slides, and the boxed collection of air-dried material (completed).

  4. To target selected geographical areas for registration and collation of associated information for information required for other projects. All specimens from Alaska and the Azores have been registered and a database prepared in association with floristic research projects.
  5. To register all specimens of rare and endangered species which require action plans for conservation and are listed in the ‘UK Biodiversity Action Plan’.
  6. To undertake rapid registration and data entry of general specimens. This involves registration of each specimen with a bar-code but entry of only selected fields of associated information into a database. The aim is to speed the process of specimen registration and 6000 specimens of Phaeophyta have been registered in this way (despite this accelerated approach it is estimated that 2-3 man-years will be required to register the entire marine algal collection).

    To date, approximately 40000 specimens have been registered, 11% of the total collection.

Taxonomic scope

Although the marine algal (seaweed) collection is large, it is taxonomically incomplete; the full systematic scope of the collection will be available when the review of the collection has been finished in a few years time. Revision of the Phaeophyta is complete and an inventory of genera and species held at BM is now available. The collection at present contains 946 species (approx. 65% of the world total of 1500) and 219 genera out of 265 (82% of the world total); all 44 families and 14 orders are represented (following the classification used in Silva et al. 1996). Thus far 1191 species of Rhodophyta have been reviewed, approximately 50% of the collection. A preliminary assay of the Chlorophyta collection suggests approximately 1400 species to be present.

Geographical information

The marine algal collection at BM is global in extent with specimens from most continents and oceans but not from all countries. Until recently the provision of geographical information was not straightforward. In the 1980s when a catalogue of type specimens and a revision of the nomenclatural and taxonomic state of the collection was commenced, it was recognised that a long period would elapse before all specimens were registered and the associated geographical information became fully available. As floristic information on the collection was often requested a decision was made to summarise geographical and floristic information for all species and countries (e.g., Tittley and Sutton 1984). These indexes are being maintained until the specimen registration databases are complete and sorting of the geographical fields can provide full information. In collaboration with researchers elsewhere specimen databases have been prepared for given areas. As mentioned, this was successfully completed for Alaska. We welcome the opportunity to collaborate on such projects for other parts of the world.

GIS (Geographical Information System) allows the creation of mapped specimen information, supporting biogeographical, distributional and other studies. Geographical information has been collated for the BM collections from Great Britain and Ireland and this will soon be available as a series of species distribution maps. Precise locational information was mapped by placing points in 5 km grid squares of the British National Grid. Date information was collected and assigned to three broad time-periods (pre 1900; 1900-69; 1970-) in order to give a temporal perspective to the maps (potentially maps can be produced with as many time periods as is required). Irish data are currently being collected. Figure 5 shows the distribution in Great Britain of Alaria esculenta (Linnaeus) Greville with coloured points representing the time periods. Figure 6 (without time periods) shows the distribution of the northern, cold water, Odonthalia dentata (Linnaeus) Lyngbye from specimens in the BM collection. Figure 7 (without time periods) shows the predominantly western distribution in Great Britain of Chondracanthus acicularis (Roth) Fredericq. Figure 8 (without time periods) shows the distribution of herbarium records of the recent migrant to Britain, Colpomenia peregrina (Sauvageau) G.Hamel. As with the geographical index to the whole collection, this accumulation of grid-references for each UK species will be maintained until replaced by a full specimen database.


Collections development, forming a strategy

Housing and maintaining collections makes demands on resources and is expensive. In the twentieth century the cryptogamic herbarium at BM has undergone several moves and transformations to improve housing, to increase storage space, and provide better working conditions for staff and visitors. Although there is at present sufficient space to accommodate moderate growth in the seaweed collection, future expansion and development will be limited inevitably by the constraints of a nineteenth century building. Housing and maintenance will be considerably improved following completion of a planned ‘state of the art’ building to house the BM collections (the ‘Darwin centre’).

The strategy for the future development of the marine algal collections in the short to medium term will focus on six key issues:

  1. Care and conservation. BM will maintain a major resource of specimens to support systematic and floristic research. Collections conservation and management, having been benchmarked against other leading institutions, will be of world-leading quality (Natural History Museum 10 year vision; internal document).
  2. Access to the collection—specimen databases. The acquisition of specimen data and also the creation of a digital image collection will continue as a high priority activity to safeguard the information content of the collections and to improve access. The museum will be a key global provider of information on specimens held (Natural History Museum 10 year vision).
  3. New specimen storage techniques. Aside from properly environmentally controlled conditions, there is a need to respond to new technologies in taxonomic research. Molecular studies, for example, will require the storage of algal material using different (e.g., deep-frozen, ethanol fixation) techniques and new ancilliary collections for that purpose will be created (see also Goldblatt et al. 1992; Rainbow 2001).
  4. Modern nomenclature and taxonomy. There is a need to keep up to date with taxonomic and modern nomenclature by scanning recently published literature or by using nomenclatural databases (see Algaebase on This will achieve a consistent arrangement of specimens and the associated data collections, and avoid past problems where specimens of a genus or species have been filed under various synonyms. Annotation of specimens studied by specialists is an important contribution that can be made to organisation of the collection.
  5. Growth. Plans for future housing of the collection allow for continued but slow growth. Specimens will continue to be acquired as a result the research interests of staff and occasional donations from external sources.
  6. UK biodiversity. In addition to supporting taxonomic research, the collections from Great Britain and Northern Ireland will be developed to serve also as a comprehensive archive of UK national biodiversity (see below).

These issues will inevitably require precisely defined working procedures and protocols for acquiring, registering, and organising the seaweed collection unlike the laissez-faire approaches of the past. Collection management at BM is becoming a team activity that involves conservators maintaining the integrity of specimens and labels, I.T. specialists designing and maintaining computer systems that hold specimen data, taxonomist-curators registering specimens and organising the collection (physically and electronically) following accepted modern nomenclature, collections-registrars providing legal information on specimen acquisition and loan, and field-researchers obtaining and following the relevant permits and protocols for specimen collection. At BM a protocol for the arrangement and management of the marine algal (seaweed) specimen collection and associated electronic data is in preparation; it is required for reasons of consistency, long-term continuity, and information sharing.

UK seaweed collections: a national resource

The seaweed collections at BM will always be important in underpinning local taxonomic and floristic research. The 130000 specimens from the UK and Ireland are also an important resource of local seaweed biodiversity information. A recently completed systematic review of the UK and Ireland holdings has provided information on the scope of the collection (to be made available electronically). Its core is the many tens of thousands of specimens collected during the nineteenth century. The survey also revealed that paradoxically, despite major floristic and ecological projects such as the Seaweeds of the British Isles flora series and the Marine Nature Conservation Review (an extensive habitat survey around the UK), the number of specimens acquired in the twentieth century has been smaller than previously. The distribution maps of the UK and Irish specimen holdings will provide a useful resource of information with each species map summarising the geographical extent of the collection. The combined geographical information creates a valuable data-source for local biogeographical analysis. The collection review has revealed taxonomic and geographical gaps, and absences in time with species such as Buffhamia speciosa Batters (Figure 4) not found since the nineteenth century. Also identified are locations for which BM holds a time-series of specimen based species records. Such information has contributed to environmental studies in the creation a historical profile of the seaweed vegetation at a particular site (see early collections above; Scott and Tittley 1999; Tittley 1977; 2001a, b).

The UK marine algal collection also provides a resource of species information to support the management of biodiversity locally, regionally, and nationally including the recognition of ‘Red Data Book’ or ‘Rare and endangered’ species (e.g., Anon 1995; Maggs 2000). Partnerships are being developed to release centrally held information at BM for local use at regional Biological Records Centres.

The strategy for the development of the UK marine algal collection will follow those outlined for the algal collection, but with additional objectives to reflect its importance in national and local biodiversity. The main additional issues are:

  1. A comprehensive collection. We aim to hold specimens of all species listed for Great Britain and Northern Ireland by filling three main types of gap in the collection, taxonomic, geographical and temporal.
  2. UK Biodiversity. We aim to organise the UK collection and associated electronic data to support the UK Biodiversity Network nationally and locally. Species mapping and registering specimens of ‘rare and endangered’ species represents a first step.
  3. Historical time-series. We aim to maintain a historical time-series of specimens at BM for selected UK sites.
  4. Contemporary issues. We aim to encourage wider use of the national collection for contemporary environmental, conservation and biodiversity issues. This may lead to the acquisition of important voucher specimens.

Marine algal (seaweed) collections: sharing a global resource

Many of the established algal collections in the world were founded in the nineteenth century as a consequence of the old order of political and economic power. However, the ‘Rio Summit’ drew attention to the importance of the biological heritage of each state. Field-research may now require the study collection to be retained in the country of origin and duplicates removed only with permission of the host country. The return of collections to their countries of origin is a topical and sensitive issue. Some states strictly control the export of biological material and there are also now stronger international and national laws governing the movement of biological material from country to country. This may slow the growth of collections particularly at the long-established centres and bring about the creation of new algal herbaria. We would welcome the opportunity to form partnerships with institutions abroad to make new collections in the field and to organise the repatriation of information (specimen data and images) held at BM.

Collecting is a necessary but potentially damaging activity, especially when large numbers of duplicate sets are prepared. There is anecdotal evidence that in the nineteenth century algal populations in Devon (southwest England) were permanently damaged through intensive collecting. The continuing development of new computer-based technology and the relative ease of assembling specimen data and images suggest a reduced need for collecting many duplicate sets of specimens. Nonetheless, in the short to medium term BM will continue to welcome the donation of collections especially those that are unsual or novel. The creation of the virtual herbarium with the availability of images of BM algal type and historically important specimens via the world-wide-web may reduce the need for large loans of specimens and thus the cost to the museum. The loan of specimens is a time-consuming and expensive activity but it is a service we will continue to provide to the scientific community.

BM recognises the need to participate in a network of marine algal collection and biodiversity information. The costs and benefits of this are considered by Brooke (2000b), Graves (2000), Scoble (2000), and Wirtz (2000). Regional and national biodiversity databases and information systems such as NABIN (North America Biodiversity Information Network) are now accessible. In Europe, BIOCISE (Biological Collection Service in Europe), ERMS (European Register of Marine Species), and BIOMARE (network of marine biodiversity research in Europe) are examples of electronic information systems to which BM can contribute algal data. A global strategy for documenting plant diversity is being actively promoted through the Convention of Biological Diversity (CBD), sixth Convention of Parties (COP6), the Global Taxonomy Initiative (GTI), and the Global Biodiversity Facility (GBIF). BM is currently the UK focal point for the GTI. Both GTI and GBIF are working to coordinate collections data (see GTI on GBIF aims to create a network of biodiversity databases and the information technology tools to allow access to the world's biodiversity information. Planned objectives for the next decade include an electronic catalogue of names of 90% of known organisms and 85% of natural history specimen data to be digitised and available via the internet. As mentioned, it is the Natural History Museum's 10 year vision to make available specimen images and data-sets of its algal and other collections.


The future development and growth of the marine algal collection at BM is planned to continue, albeit more slowly than in the past. In the short to medium term, aside from routine care and maintenance and the loan of specimens, the development of databases and image collections will be a high priority task thereby improving access to the collections. Particular emphasis will be placed on making the BM marine algal collection from the United Kingdom an important national resource of algal biodiversity information. BM will contribute to the global resource of marine algal species and specimen information. The nomenclatural and taxonomic studies completed by Paul Silva and others underpin the effective organisation of a major collection of marine algal (seaweed) specimens and its associated information.


I wish to acknowledge in particular Jim Price, formerly of the Natural History Museum, for his incredible efforts in bringing together much of the information on collectors, collections and also biographical information, and also for the collation of the surprisingly large amount of pre-Linnaean specimen and collector information for Kent. I would also like to thank the many Earthwatch volunteers for their diligent efforts in extracting geographical information for mapping the British seaweed collection. Earthwatch Institute is gratefully acknowledged for funding this project. Thanks are also due to Jim Chimonides of the Department of Zoology (BM) for his considerable help with the preparation of distribution maps.


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