2011 Bazzicalupo.Pdf (11.03Mb)

2011 Bazzicalupo.Pdf (11.03Mb)

The taxonomy and host specificity of Russula species of the section Ingratae and subsection Foetentinae at Dawyck Botanic Garden. Anna Bazzicalupo 26th August 2011 Thesis submitted in partial fulfilment for the MSc in the Biodiversity and Taxonomy of Plants 2 3 ABSTRACT In this study, using laboratory based techniques, the accuracy of species identification carried out in the field for the section Ingratae Quél. (sensu Romagnesi) and subsection Foetentinae Meltz. Zvár. of the genus Russula Pers. (Russulales, Basidiomycota) is investigated. Samples from the RBGE herbarium were used. ITS rDNA sequences from the samples were determined and different methods of analysis were used to produce molecular trees. Spore ornamentation was observed using light microscopy and SEM. The study found that the subsection Foetentinae constitute a monophyletic group and that spore ornamentation reflected well the clades in the molecular trees. A few taxa, placed in this section in previous treatments were found to be related to other Russula species. Due to poor resolution, not all clades could be assigned a species name. The names on the herbarium labels were not consistent with the morphological or molecular characters, indicating that field characters had not been effective in identifying the species consistently. The study strongly suggests that spore ornamentation is a good character in discerning species in the Ingratae. The study also looked at host specificity of Ingratae collected at Dawyck Botanic Garden (Scotland). Sampling and taxonomic problems are identified and discussed. 4 Acknowledgements I would like to thank my supervisors: Dr. Stephan Helfer, Prof. Roy Watling and Dr. Rebecca Yahr, for their insight, feedback and dedicated work. I would like to thank Dr Michelle Hollingsworth, Ruth McGregor and Frieda Christie for their technical help in the lab and SEM, and Graham Hardy for helping me dig out obscure literature. Also I would like to thank Nev Kilkenny for providing me, when he could, with fresh specimens of the Foetentinae. 5 CONTENTS 1. INTRODUCTION 7 1.1 The genus Russula, the section Ingratae and the subsection Foetentinae 7 1.2 Molecular studies of Russula 10 1.3 The Ecology of Russula at Dawyck Botanic Garden 12 2. PROJECT AIMS 14 3. TAXONOMIC ACCOUNT 15 4. MATERIALS & METHODS 25 4.1 Molecular Analyses 25 4.1.1 Taxon Sampling 25 4.1.2 Nucleic acid preparation, amplification and sequencing 25 4.2 Phylogenetic Analysis 28 4.3 Morphology 29 4.3.1 Light Microscopy 29 4.3.2 SEM 30 4.4 Fresh specimens from Dawyck Botanic Garden 30 5. RESULTS 31 5.1 Results of the molecular analysis 31 5.2 Morphological characters and their distribution on the molecular trees 32 5.3 Fresh specimens collected at Dawyck Botanic Garden 50 6. DISCUSSION 51 6.1 Considerations on datasets 51 6.2 Outgroups and excluded species 51 6.3 The Foetentinae 53 6.4 Pileipellis as a useful diagnostic character 55 6.5 Nomenclature issues 56 6.6 Exotic and native associations of the Foetentinae 57 7. SPECIMENS SEEN 59 8. CONCLUSION 61 9. CITED LITERATURE 63 LIST OF FIGURES 1. Schematic representation of a Romagnesi key 9 2. One of the most parsimonious trees 33 3. Strict Consensus tree 34 4. Neighbour Joining tree 35 5. Maximum Likelihood tree 36 6 6. Structures of the pileipellis compared with drawings 38 7. Spore ornamentation and herbarium specimen labels 39 8. SEM spore ornamentation of Fellinae and R. farinipes 40 9. SEM spore ornamentation of the R. sororia group 41 10. SEM spore ornamentation of the R. illota group 41 11. SEM spore ornamentation of the R. pectinatoides/R. praetervisa group 42 12. SEM spore ornamentation of group A (Foetens) 43 13. SEM spore ornamentation of group B (Laurocerasi or Grata) 45 14.SEM spore ornamentation of group C (Pectinata) 46 15. Schematic drawing of spore ornamentation found in the study 48 16. R. foetens collected at Dawyck Botanic Garden 50 17. Group A from the molecular trees 54 LIST OF TABLES 1. Specimens used in the molecular analysis 26 2. Information on sequences taken from Genbank and UNITE databases 27 3. ITS Primers and references 27 7 1. INTRODUCTION 1.1 The genus Russula, the section Ingratae, and the subsection Foetentinae The family Russulaceae (Lotsy) is comprised of two main genera: Russula Pers. and Lactarius Pers., in addition to several minor genera. The family is characterised by having sphaerocysts (round cells as opposed to filamentous cells) in the trama, which give the carpophores the characteristic crumbly consistency; and amyloid spore ornamentation, by which the starch in the ornamentation of the spores will stain black-purplish with Melzer’s iodine solution (Kränzlin, 2005). The genus Russula is distinguished from Lactarius by the lack of latex excretion and the presence of sphaerocysts in the trama of the lamellae (Singer 1975). The genus Russula Pers. ex S.F. Grey was first described by Persoon based on R. lutea (Hudson ex Fr.) or R. emetica (Schaeff. ex Fr.) Pers. ex S.F. Grey. The number of species in the genus is unknown and varies according to the source consulted, 275 fully recognised according to Singer (1975). Numbers of species have been given in regional context, such as 85 species described for the Pacific Northwest (Woo, 1989), or 135 for Switzerland (Kränzlin, 2005), but the total number of species is a rough estimate of 750 ca. (Rinaldi et al., 2008). This genus is distributed worldwide, but while taxonomic treatments were mainly European (Persoon, 1801; Fries, 1874; Quélét, 1888; Britzelmayr, 1893; Barbier, 1907; Massee, 1902; Bataille, 1908; Maire, 1910; Ricken, 1915; Melzer & Zvara, 1927; Crawshay, 1930; Konrad & Josserand, 1934; Singer, 1926, 1932; Lange, 1940; Schaeffer, 1952; Romagnesi, 1967; Bon, 1989; Reumaux, Bidaud & Moënne-Loccoz, 1996; Sarnari, 1998), but there have been treatments of the genus in North America (Peck, 1906; Burlingham, 1915; Singer, 1957; Bills & Miller, 1984), Africa (Heim, 1938; Buyck, 1989), and South America (Pegler & Singer, 1980; Buyck, 1988). Maire (1910) summarises the main attempts to organise the genus Russula, by Persoon, Fries, Quélet, Bataille and Massee. He suggests that the most natural classification of Russula was given by Fries, who classified regarding all characters known at his time with the same weight; he also states that the most artificial classification was formulated by Quélet and Bataille who put much emphasis, without an adequate explanation by the authors, on the colour of the spores character. Maire (1910) organised the key morphological characters in: macroscopic, microscopic and chemical. 8 The genus Russula is easily identified by amateurs, identification problems arise when trying to distinguish the species within the genus. The genus is divided in sections or sometimes subgenera. Romagnesi (1967) adopted two subgenera, eight sections and 34 subsections; Singer (1975) eight sections, 34 subsections, not same as Romagnesi (1967); Sarnari (1998) six subgenera, 17 sections and 28 subsections. Even though they are different classifications, overall the groups are generally similar, following certain morphological characters (Miller & Buyck, 2002). The section treated in this study is the Ingratae Quél. as understood by Romagnesi (1967). The section Ingratae was first described by Quélét (1888); this section has been treated over the century several times, (Maire, 1910; Melzer & Zvara, 1927; Singer, 1932; Shaeffer, 1933; Heim, 1938), for the purposes of this study the Ingratae sensu Romagnesi (1967) will be considered as a starting point. Even though there have been later treatments (e.g. Bon, 1989), they have not changed radically from Romagnesi’s treatment. Romagnesi groups the Ingratae because of characteristics that are unusual in the genus, such as their fragrant nature (from foetid to Benzaldehyde – smelling of almonds and marzipan); with a light coloured spore print, which is variable, from pure white (following chromatic keys by Crawshay a, Romagnesi Ia) to cream (Crawshay c, Romagnesi IIb). According to Singer (1975), who does not follow Romagnesi’s classification for the whole genus, but generally does for this section, the Ingratae are characterised by grey, brown, ochraceous buff or melleous, lemon yellow, or greenish cream colour (or a combination of these colours) of the carpophore. Usually characterised by an acrid taste (of which some sweet varieties can be distinguished according to Romagnesi, 1967), with often a foetid, nauseating, pungent or Benzaldhyde odour. The Type species for this section is R. foetens Pers. ex Fr. (Singer, 1975). Like the genus, the section Ingratae has been treated differently over the years by different authors, and taxonomic treatments never stabilised completely. Until recently, this section was divided into two subsections: the Foetentinae Meltz. Zvár. and the Fellinae Meltz. Zvár; this is the treatment that Shaeffer (1935) gives the section, he places this section under the category of white- spored russulas. Romagnesi (1967) includes the subsections Foetentinae and Fellinae in the Ingratae as well. This treatment was still used in 2003 and 2005 by Cazzoli, for an amateur-oriented explanation of the genus; however, Bon (1989)’s taxonomic treatment removed the Fellinae from the section and divided the Ingratae into Foetentinae and Pectinatinae. The Foetentinae sensu Romagnesi, which is the closer focus of this study, were described by Melzer and Zvara (1927) with the characteristic of having: no velar remnant present; a pileus of dull colours, ochraceous or pallid; a

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