Species of Hypholoma ( Fr . ) P . Kumm . ( Strophariaceae , Agaricales ) in Rio Grande do Sul State , Brazil 1

(Species of Hypholoma (Fr.) P. Kumm. (Strophariaceae, Agaricales) in Rio Grande do Sul State, Brazil). Detailed descriptions, illustrations, discussions and a key for identification of the known species of the genus Hypholoma (Fr.) P. Kumm. in Rio Grande do Sul state are presented, as well as a revision of the Hypholoma specimens deposited in the Fungi Rickiani collection. Based on the authors’ collections and the herbarium revision, the following species were recognized: H. aurantiacum (Cooke) Faus, H. ericaeum (Pers.: Fr.) Kühner, and H. subviride (Berk. & M.A. Curtis) Dennis.

The nomenclature of the genus has been discussed over the years by different authors (Baletto 1989;Dennis et al. 1954;Farr & Farr 1981;Singer & Smith 1946).Several Hypholoma species were placed in the past in the genus Nematoloma P. Karst.(Singer 1986;Smith 1951), which finally suffered nomenclatural rejection (Korf 1986).Recently, species of the genus were considered by Noordeloos (1995;1999) as subgenera of Psilocybe s.l., based on Smith (1979) and Kühner (1980), but this proposal was not well accepted among mycologists (Bon & Roux 2003;Norvell & Redhead 2000) and overall it was not supported by recent molecular studies (Moncalvo et al. 2002).According to Moncalvo et al. (2002), Hypholoma is recognized as an independent clade, composed of most of its species, except H. subericaeum (Fr.)Kühner and H. aurantiacum (Cooke) Faus [as S. aurantiaca (Cooke) M. Imai], which have an uncertain position in the "stropharioid" clade.
Species of Hypholoma are not edible; in fact, those belonging to the group of H. fasciculare (Huds.: Fr.) P. Kumm. are considered poisonous (Badalyan et al. 1995).This species has also been investigated for its antioxidant (Badalyan 2003) and hypoglycemic (Badalyan & Serrano 1999) activities.As active wood and litter decomposers, they also play an important role in forest ecosystems, being currently used in bioconversion of cellulose, fabric and dye industrial residues (Hofrichter & Fritsche 1997;Steffen et al. 2000), and also in biological control of phytopathogenic fungi (Badalyan et al. 2002;Chapman et al. 2004).
In the present work we revised the known species of Hypholoma from Rio Grande do Sul state, based on the authors' collections and material deposited in regional and national herbaria, especially those of the Fungi Rickiani collection.

Materials and methods
Specimens were collected from March 2004 to September 2005, in different localities of Rio Grande do Sul state (Fig. 1).Material deposited in the following herbaria, listed according to the Index Herbariorum (Holmgren & Holmgren 1998-2005), were also studied: HASU, HCB, ICN, PACA, SMDB, and SP.All collected material is deposited in the herbarium ICN.
The macroscopic analysis followed Largent (1977), while the microscopic study of the basidiomata followed Largent et al. (1986).As mounting media 5% KOH (potassium hydroxide) alone or with 1% Congo Red were used.Line drawings were made with a camera lucida in a Leica DM LS2 optical microscope.For the basidiospore descriptions, Q is the ratio of length to width, Q m is the medium value of Q, and n is the number of measured basidiospores.Color terminology was taken from Munsell (1994), unless not indicated.All scientific names, independent of taxonomic rank are italicized, following Hawksworth (2001), and all taxonomic authorities are abbreviated according to the Authors of Fungal Names (CABI 2005).

Results and discussion
In this study, three species of the genus Hypholoma were recognized as occurring in Rio Grande do Sul.The following key is provided for their identification.Discussion: This species is frequently referred to in the European literature as Stropharia aurantiaca (Cooke) M. Imai (Pegler & Legon 1998) or S. aurantiaca (Cooke) P.D. Orton (Watling & Gregory 1987) due to the presence of fibrillose annulus, but the absolute lack of acanthocytes in the rhizomorphs excludes it from that genus.Flammula puiggarii, described by Spegazzini (1889) has been used in South-American literature to name this mushroom (Raithelhuber 1985;Wright & Albertó 2002; both as Hypholoma puiggarii).However, the holotype of Spegazzini is identical to Stropharia rugosoannulata Farl.ex Murrill, as previously indicated by Singer (1950) and Pegler (1997).Spegazzini's F. puiggarii (1889) is an older name than S. rugosoannulata (Murrill 1922), but the latter is a well-kwon name used for a cultivated mushroom; the proposal for the rejection of the former and conservation of the name S. rugosoannulata is needed.The specimens studied by Singer (1969) as Nematoloma puiggarii (Speg.)Singer, except for the type of F. puiggarii, possibly corresponds to H. aurantiacum as here presented.
The purplish color of the basidiomata and the viscid to subviscid pileus surface, as well the fibrillose annulus and the presence of abundant rhizomorphs are characteristic of this species.Scanning electronmicroscopy studies (Farr 1985) revealed the presence of a singular ornamentation of the basidiospore wall, composed of slightly rugulate and baculate elements, however under light microscope the basidiospores are smooth.Molecular systematics have pointed out that H. aurantiacum has close affinities with the mushroom Stropharia magnivelaris Peck and the secotioids Leratiomyces similis (Pat.)Bresinsky & Binder and Weraroa erythrocephala (Tul.& C. Tul.) Singer & A.H. Sm., suggesting its exclusion from the genus Hypholoma (Moncalvo et al. 2002).
In Brazil, H. aurantiacum was first reported from Rio Grande do Sul state by Rick (1907) as Stropharia thrausta Kalchbr., which was later cited by Guzmán (1975) as Naematoloma sp.; we confirmed these specimens as H. aurantiacum as described above.It was also cited by Sobestiansky (2005) from the region of the Southern Plateau of Rio Grande do Sul (Nova Petrópolis) and by de Meijer (2001) from the state of Paraná, both as S. aurantiaca.The latter author also reported H. puiggarii in the same paper, but he did not discuss the differences between these two names.
This species has been reported as common in Europe (Noordeloos 1999), but Smith (1951) considered it rare in North America.We also considered it a common agaric in Rio Grande do Sul, fruiting mainly in autumn.

Synonyms, excluded or doubtful species
The names of the following taxa (including their authorities) are presented exactly as they were published by Rick in his numerous papers (see Bibliographic References).Several species reported by Rick (1961) do not have preserved specimens; others, however, never were published or reported by Rick, but were located at the herbarium PACA and therefore they are included here.
H. cascum Fr. -Cited by Rick (1961), but without specimens indicated, probably no material preserved in the herbarium PACA.If correctly identified, the species refers to Psathyrella casca (Fr.)Konrad & Maubl., however we consider it a doubtful record.
H. dispersum Fr. -No material preserved in the herbarium PACA and also specimens not cited in Rick (1961) where this species was reported.If Rick identified his specimens correctly, this would represent a fourth species of the genus in Rio Grande do Sul, however we consider it a doubtful species at present.
H. hydrophilum Bull.-Probably no material preserved in the herbarium PACA and specimens not indicated in Rick (1961).If correctly identified, the species refers to a member of the genus Psathyrella, currently known as P. hydrophila (Bull.)Maire.
H. intonsum Passer.-This is a doubtful species or a possible synonym of some known species in its original sense because there is no modern information about this name.The specimen reported by Rick (1961) is in fact a Stropharia sp.due to the presence of abundant acanthocytes in the rhizomorphs; his description (Rick 1907(Rick , 1939(Rick , 1961) ) is identical (if not a transcription) of those presented by Saccardo (1887).Material examined: BRAZIL.Rio Grande do Sul: Esteio, 1939, Rick 13.332 (PACA 8.692).
H. lanaripes Cooke -Probably no material preserved and specimens were not indicated in the report by Rick (1961).This could to represent H. lanaripes (Cooke) Fr., but without preserved material, we consider it a doubtful record.
H. leucotephrum Berk.-The mushrooms belong to Psathyrella, possibly P. leucotephra (Berk.& Br.) P.D. Orton or P. candolleana, but the badly preserved specimens did not allowed a complete study.Material

Figure 1 .
Figure 1.Map of Rio Grande do Sul (RS), showing the collecting sites of the studied taxa.