Exsiccatae in the bryophyte collection of the National Herbarium , Pretoria

Exsiccatae in the bryophyte collection of the National Herbarium in Pretoria (PRE) are catalogued for the fi rst time. Most of the 66 series represented in PRE were issued in Europe, but the USA is the country where the largest number of exsiccatae originated. The exsiccatae span three centuries, with the earliest specimens issued in 1845 and the latest in 2009. This indicates the long-standing exchange of material and transfer of knowledge between herbaria in South Africa and countries of the northern Hemisphere. Many of the exsiccatae in PRE are incomplete and specimens were received as duplicates in exchange sets rather than exsiccatae. PRE houses a number of important African and southern hemisphere exsiccatae including two different sets of A. Rehmann’s Musci Austro-Africani (1875–1877) and Musci Austro-Africani cont., and R. Ochyra’s Bryophyta Antarctica exsiccata.


INTRODUCTION
The Cryptogamic Herbarium of the South African National Biodiversity Institute (SANBI), which forms part of the National Herbarium in Pretoria (PRE) (acronyms according to Holmgren et al. 1990), consists of three separate collections: (1) the mosses, (2) liverworts and hornworts, and (3) lichens.The PRE bryophyte collection (mosses, liverworts and hornworts), as well as other bryophyte collections in southern Africa, were described by Magill (1980).The bryophyte collections of the Rhodes University Herbarium (RUH), Compton Herbarium (NBG, including SAM), KwaZulu-Natal Herbarium (NH, on permanent loan), and Stellenbosch Herbarium (STE) were since incorporated into PRE.
The PRE bryophyte collection consists of approximately 69 000 specimens, of which 35 500 are from southern Africa (the region south of the Limpopo and Kunene rivers) and recorded in SANBI's PRECIS database (Magill et al. 1983).The remainder of the collection comes from many parts of the world and consists mainly of duplicate specimens received as gifts and through an intermittent exchange programme with more than 20 overseas herbaria.A substantial number of exsiccatae specimens, distributed throughout the main collection, were received through the exchange programme.
Exsiccatae (plural form of exsiccata, from the Latin exsiccatus for 'dried up') are series of published, uniform, numbered sets of dried specimens with printed labels (Sayre 1969;Pfi ster 1985;Triebel et al. 2004).Exsiccatae usually have descriptive titles with an indication of the editor and the place and date of issue or publication.They are distributed in several identical sets of duplicate specimens, usually accompanied by printed booklets of labels or schedae (e.g. Figure 1A).According to Art. 30.4 of the International Code of Botanical Nomenclature (McNeill et al. 2006), printed matter accompanying exsiccatae are, from 1 January 1953, only effectively published if it is also distributed independently of the exsiccatae.Exsiccatae were often distributed in units of 100 specimens, a century; each century generally constituted a volume in the series.
Type specimens and exsiccatae are generally regarded as the most valuable collections in a herbarium.Magill (1980) compiled a catalogue of southern African moss type specimens in PRE.The aim of this paper is to document and determine the extent of exsiccatae in the PRE bryophyte collection.Hopefully this will point to exsiccatae as well as parts of exsiccatae that are sought after by researchers.

MATERIALS AND METHODS
Data on exsiccatae in PRE were gathered from specimens and published schedae in the PRE bryophyte herbarium, the series Cryptogamae Exsiccatae by Sayre (1969Sayre ( , 1971Sayre ( , 1975)), IndExs-Indexs of Exsiccatae, a web-accessible database of exsiccatae established by Triebel & Scholz (2001) and maintained by staff members of the Botanische Staatssammlung München (M), as well as other publications referred to in the text and in Table 1.Terminology follows that of Triebel et al. (2004).
Only exsiccatae in the strict sense of Sayre (1969Sayre ( , 1975) ) are listed; therefore series in PRE that do not meet all the requirements of a published exsiccata, e.g.Herb.Ind. Or. Hook. fi l. & Thompson (Sayre 1975: 343) and Sammlung deutscher Laubmoose, Lebermoose und Flechten, Vol.I. Laub-und Lebermoose by D. Dietrich, published in Jena (Germany) in 1861, which was issued National Herbarium, South African National Biodiversity Institute, Private Bag X101, Pretoria 0001.E-mail: j.vanrooy@sanbi.org.za.MS. received: 2012-08-01.  in book form with the specimens mounted on the pages next to printed names, but without numbers and localities, are excluded.
In Table 1, the bryophyte exsiccatae in PRE are listed alphabetically by full title according to IndExs.Exsiccatae in IndExs, which obviously belong to the same series, e.g.Musci Japonici exsiccati Det. A. Noguchi (Ser. 1, and Musci Japonici exsiccati det.Akira Noguchi (Ser.2, 51-100), were combined.The second column contains notes on the labels in PRE, e.g. the title (if different from the full title), printing and colour.This is followed by the parts present in PRE and the numbers issued in each, with an indication of the numbers present in PRE.The remaining columns contain the date, institution, place and country of editing, publication or distribution, as well as the name of the editor or distributor.The analysis of exsiccatae in the bryophyte collection is based on data in Table 1.

RESULTS AND DISCUSSION
The PRE bryophyte collection houses 66 exsiccatae (Table 1), which represent 6% of all cryptogam and fungus exsiccatae issued up to 2003 (Triebel et al. 2004) and 13% of cryptogam exsiccatae that contain bryophytes.
The majority of exsiccatae in PRE (34) were fi rst issued in the 19th century, almost as many (32) in the 20th century, and none in the 21st century.The oldest exsiccatae specimens in PRE are from Century 2 of Flora Germanica exsiccata.Serie II.Cryptogamia, edited by J.C. Breutel and issued in Leipzig, Germany in 1843 (Figure 1B).The most recent specimens in PRE belong to Fascicle XXX of Bryophyta selecta exsiccata, edited by H. Inoue and issued in 2009 by the National Science Museum (TNS), Tokyo, Japan (Figure 1C).This indicates long-standing co-operation and exchange of scientifi c knowledge between herbaria in South Africa and countries of the northern Hemisphere.
Although exsiccatae usually have printed labels (see Figure 1B, C, G, H), there are series in PRE with handwritten labels, e.g.Sphagnaceae Britannicae exsiccatae, edidit R. Braithwaite, which was issued in 1877 (Figure 1D), typewritten labels, e.g.Fascicles 1-3 of Musci macroregioni meridionali Poloniae exsiccati.Mosses of southern macro-region of Poland, issued by SOSN from 1982 to 1984, and a combination of the above, e.g. S. Berggren's Plantae in Itineribus Suecorum Polaribus collectae/Insulae Spitsbergenses from 1874, with title, main locality and collector printed and rest handwritten (Figure 1E), and R. Ochyra's Bryophyta Antarctica exsiccata, issued in 1982, with the title, editor, place of issue and name printed, and the rest typewritten (Figure 1F).Several of the 19th century series have printed labels without titles, which make them diffi cult to recognize, e.g.C.F. Austin's Musci Appalachiani, as well as Hepaticae Boreali-Americanae exsiccatae (Figure 1G) issued in 1870 and 1873 respectively, and Carrington & Pearson's Hepaticae Britannicae exsiccatae of which Fascicles 1-3, issued from 1878 to 1883, are represented in PRE.
Most exsiccatae in PRE were issued in Europe (44), followed by North America (18), Asia (3) and Australasia (1).However, the United States of America ( 14) is the country where most exsiccatae in PRE originated from, followed by Germany with seven, Poland with six, and France and Sweden with fi ve exsiccatae each.
The majority of bryophyte exsiccatae in PRE are incomplete (Table 1), some only represented by single specimens, which indicates that they were distributed as duplicates in exchange sets rather than exsiccatae, e.g.North American Musci perfecti; issued by A. J. Grout Ph.D. in Newfane, Vermont from 1925 to 1940, of which there are only a few specimens in PRE, received on exchange from the W.S. Turrell Herbarium, Miami University (MU) in 1990 (Figure 1H).Another example is Musci Britannici, edited by W. Wilson and originally issued in Warrington, UK after 1855, but the few scattered numbers in PRE were only received in the latter part of the 20th century through exchange with The New York Botanical Garden (NY).
Another important African exsiccata in PRE, the only to cover the whole of sub-Saharan Africa, is Bryophyta Africana Selecta, edited by Ryszard Ochyra and Tamás Pócs and issued jointly by the W. Szafer Institute of Botany in Kraków, Poland, andthe Eszterházy Károly Teachers Training College, Eger, Hungary in 1992 and1993.Frans Verdoorn's Hepaticae selecti et critici, as well as Musci selecti et critici, issued in the 1930's, contain bryophytes from several continents, including Africa.
PRE also contains important bryophyte exsiccatae from other parts of the southern hemisphere, e.g.Bryophyta Antarctica exsiccata, edited by Ryszard Ochyra and distributed by the University of Alberta, Edmonton, Canada in 1982 (Figure 1F), which is the fi rst and only exsiccata of Antarctic bryophytes.The Australian series Musci Australasiae exsiccatae, edited by H. Streiman (Figure 1A), is one of the largest exsiccata in PRE with 600 specimens.