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Summary The development of a universal approach to the identification of fungi from the environment is impeded by the limited number and narrow phylogenetic range of the named internal transcribed spacer DNA sequences available on GenBank. The goal here was to assess the potential impact of systematic DNA sequencing from a fungal herbarium collection. DNA sequences were generated from a diverse set of 279 specimens deposited at the fungal herbarium of the Royal Botanic Gardens at Kew (UK) and bioinformatic analyses were used to study their overlap with the public database. It is estimated that c. 70% of the herbarium taxonomic diversity is not yet represented in GenBank and that a further c. 10% of our sequences match solely to ‘environmental samples’ or fungi otherwise unidentified. Here it is shown that the unsampled diversity residing in fungal herbaria can substantially enlarge the coverage of GenBank's fully identified sequence pool to ameliorate the problem of environmental unknowns and to aid in the detection of truly novel fungi by molecular data.

Summary• Lichenization is one of the most important fungal lifestyles and lichen fungi are assumed to form obligate symbioses with their photobionts. Here we test if lichenized and non-lichenized samples in three cases of closely related lichenized Conotrema and saprotrophic Stictis (Stictidaceae, Ostropales, Ascomycota) in northern Scandinavia, form distinct monophyletic groups (= species).• We applied phylogenetic species recognition, by analysing fungal DNA sequence data from four independent genomic markers.• Separate parsimony and parsimony jack-knifing analyses of three independent genes are congruent and result in intermixed groups of lichenized and saprotrophic specimens. The sequence variation in an intron also supports this. Our results suggest that all three cases represent independent fungal phylogenetic species, which can undergo their whole sexual lifecycle either as lichens or as saprotrophs.• The use of different nutritional modes -optional lichenization -allows separate individuals to exploit different niches during the forest succession. We suggest that this environmental plasticity may be common in the Stictidaceae, and propose that it is an overlooked strategy in fungi adapted to unpredictable successional ecosystems.

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Maximum parsimony analysis of nuclear SSU rDNA sequences was utilized to infer the phylogenetic relationships of representatives of the macrolichen families Cladoniaceae, Sphaerophoraceae, and Stereocaulaceae (Lecanorales subord. Cladoniineae, Ascomycotina). Farris’ parsimony jackknifing, and a similar jackknife strategy with branch-swapping and multiple addition sequences in PAUP*, were performed to assess branch support. The results indicate that the Sphaerophoraceae should be emended to include Neophyllis (formerly Cladoniaceae or Stereocaulaceae) and Austropeltum (formerly Stereocaulaceae), and it is suggested that the type of boundary tissue present is a synapomorphy for the family. The families Sphaerophoraceae and Bacidiaceae form a clade, together with Psora decipiens, Tephromela atra and Scoliciosporum umbrinum. The Cladoniaceae should be emended to include Pilophorus, and the genera Metus, Cladia and Heterodea should also be included in the family. The sometimes-recognized families Cladiaceae and Heterodeaceae are shown to be derived from within Cladoniaceae. The Stereocaulaceae is recircumscribed to accommodate Stereocaulon only. Neither the possession of podetia/ pseudopodetia, a dimorphic, cladoniiform thallus, nor the presence of cephalodia, is a morphological synapomorphy for a monophyletic group in our analysis. Optimising ascus structures onto one of the most parsimonious trees suggest that tube-like apical structures may well be primitive characteristics within the Lecanorales. The two lecanoralean suborders Lecanorineae and Cladonineae are both paraphyletic groups in the present analysis. It is pointed out that if further studies confirm that Stereocaulon is the sister-group to the Cladoniaceae, as circumscribed here, then there may be no reason to accept the two families Cladoniaceae and Stereocaulaceae as distinct. Branch-swapping and several random-addition sequencesimprove resolution, adding several supported groups in the topology, and improve support values for groups already supported by parsimony jackkniring analyses, and we suggest a procedure for implementing this by using PAUP*

This work is the completion of a series of reports describing the nitrogen-fixing bacterial symbionts of sulla (Hedysarum coronarium L., Leguminosae) and providing the grounds for their proposal as a new taxon. The introduction summarizes a large amount of previous evidence gathered on the physiology, genetics and ecology of such organisms, which have in the past been referred to provisionally as 'Rhizobium hedysari'. Upon adding 16S RNA sequencing, amplified rDNA restriction analysis of the rrn operon, DNA-DNA hybridization homology and analysis of low-molecular-mass RNA species, it is concluded that the group of strains that specifically nodulate sulla consists of a coherent set of isolates that differ from previously described rhizobia to an extent that warrants the constitution of the species boundary. The name Rhizobium sullae sp. nov. is proposed, with isolate 1S123T (=USDA 4950T = DSM 14623T) as the type strain.

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