| Gymnopilus maritimus | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Agaricales |
| Family: | Hymenogastraceae |
| Genus: | Gymnopilus |
| Species: | G. maritimus |
| Binomial name | |
| Gymnopilus maritimus | |
 | |
| Gymnopilus maritimus is known only from a localised area in theProvince of Olbia-Tempio,Sardinia, Italy.[3] | |
Gymnopilus maritimus is a fungus species of the familyHymenogastraceae first collected in northernSardinia, Italy, in 2006. The species produces moderately sized, sturdymushrooms of a reddish-orange colour. Thecap, which can measure up to 70 millimetres (3 in) across, is covered in orangefibrils, and sometimes has small scales. The yellowishstem measures up to 110 mm (4 in) in length by 8 mm (0.3 in) in width, and sometimes shows remnants of thepartial veil. The mushrooms have thickgills of a variable colour, ranging from yellow to rust but staining darker, and the yellowflesh has a mild taste. The mushrooms leave a rusty-brownspore print, while the spores themselves measure from 7.5–11.5 micrometres (0.00030–0.00045 in) in length. The species is most similar in appearance toG. arenophilus andG. fulgens, but can be differentiated from bothmorphologically. Despite the similarities, it is not closely related to either, suggestingconvergent evolution. Instead, within the genusGymnopilus, it is most closely related to thespectabilis–imperialisclade. However, it is not particularly similar to any of its closest relatives.
The species has been found only on coastalsand dunes nearOlbia, in Sardinia, where it was observed growing at the base ofJuncus maritimus (the sea rush), between the winter months of October and January. However, there is speculation that it may also grow elsewhere in Europe. Mushrooms were seen growing from both the sandy soil and decaying plants; however, as asaprotrophic feeder, it is possible that the species would be able to grow on othersubstrates. The mushrooms grow in close groups or tight tufts.
| Cladogram showing thephylogeny ofG. maritimus and some related species based onmolecular analysis of sequences fromITSrDNA.[4] |
Gymnopilus maritimus was first described by mycologists Laura Guzmán-Dávalos (a specialist inGymnopilus[5]), Antonio Ortega, Marco Contu and Alfredo Vizzini in 2009 in an article in the journalMycological Progress.[6] The description was based on several specimens collected during field work by Contu in Sardinia between January 2006 and January 2007;[3][6] theholotype was collected on 15 January 2006.[7] The discovery has contributed to Sardinia's reputation as an area of mycological significance.[8] The description was later published in Italian by Contu and Vizzini in the journalMicologia e Vegetazione Mediterranea, along with the description ofG. purpuresquamulosus, because the original descriptions of both of these species were in English, and difficult for non-specialists to obtain.[5] Thespecific epithetmaritimus refers to the typical habitat of coastalsand dunes, on sandy soil or decomposingJuncus maritimus.[7] The holotype has been deposited in theUniversity of Granada's herbarium.[9]
Within the genusGymnopilus, it is located in thesubgenusGymnopilus andsectionMacrospori.[6] The subgenusGymnopilus was proposed byHenri Romagnesi asCortinatae (while the genus was known asFulvidula) in 1942, though the nameGymnopilus was given later byRolf Singer. The subgenus is characterised by mushrooms that feature either noveils, or veils that do not formrings. The sectionMacrospori, proposed by Guzmán-Dávalos in 1995, is made up of large-spored species with ringless mushrooms.[10]Molecular analysis revealed thatG. maritimus forms a sister group to (that is, shares an immediatecommon ancestor with) thespectabilis–imperialisclade, a clade that includesG. imperialis,G. spectabilis,G. junonius (often consideredsynonymous withG. spectabilis),G. pampeanus, and others.[11]G. maritimus forms a more inclusive clade along with the members ofspectabilis–imperialis; while it produces the smallest fruit bodies, it shares with the other members strong, sturdy mushrooms, caps with fibrils (sometimes with scales) and large, warty spores that turn red inMelzer's reagent orLugol's iodine.[11]
| External image | |
|---|---|
 A photograph ofGymnopilus maritimus mushrooms, taken of theholotype and published with the original description. Hosted bySpringer. |
| Gymnopilus maritimus | |
|---|---|
| Mycological characteristics | |
 | Gills onhymenium |
 | Cap is convex |
  | Hymenium is adnate or sinuate |
 | Stipe is bare |
 | Spore print is reddish-brown |
 | Ecology issaprotrophic |
 | Edibility isunknown |
Gymnopilus maritimus mushrooms have acap of between 15 and 70 millimetres (0.6 and 3 in) in width that is convex to flattened-convex in shape. There is sometimes a broadumbo, and in older specimens, the cap is depressed in the centre. The margin of the cap is somewhat wavey. The cap surface is dry and dull, coloured red to red-orange, and yellow towards the margin. It is covered in fibrils of an orange colour, and sometimes has minute scales. The dried cap turns blackish-red whenpotassium hydroxide is applied.[12] Thestem is 35 to 110 mm (1 to 4 in) in length by 4 to 8 mm (0.2 to 0.3 in) in width. It is attached centrally to the cap, and is either completely cylindrical, with equal thickness throughout its length, or slightly narrower towards the base, where whitish or creammycelia are sometimes visible. It is dry, with fibres and furrows. It is a yellowish colour, bruising reddish brown.[13] Traces of thepartial veil are sometimes visible on the stem, though it does not form a ring.[14] The yellow (brown at the bottom of the stem)flesh can be up to 15 mm (0.6 in) thick in the cap and does not bruise. It dries dark brown. There is no distinctive odour, and the taste is mild or slightly bitter.[13] The thickgills can be adnate (connected to the stem by the entire depth of the gill) or sinuate (wavy, with the gills becoming shallower than deeper). They are subdistant (neither close nor distant) and swollen in the middle. In colour, they are yellow in the youngest mushrooms, turning an ochre-orange, while the oldest mushrooms they arerust. The gill edges are paler than the faces, and the gills stain orange-brown or darker.[12] No reference is made in the original description to theedibility of the mushrooms.[15]
Gymnopilus maritimus leaves a rusty-brownspore print. Thebasidiospores can measure 7.5–11.5 micrometres (0.00030–0.00045 in) in length, though the typical range is 8–10.5 micrometres (0.00031–0.00041 in). In width, they typically measure 5.5–7.5 micrometres (0.00022–0.00030 in), but they can be up to 8 μm wide. In shape, they areellipsoid or sometimes broadly ellipsoid. The top of the spore (the side where it was once attached to thesterigma, the connection between the basidium and the spore) is rounded and blunt. The spores are covered with fairly large warts, measuring from 0.5–2 micrometres (2.0×10−5–7.9×10−5 in) from the main spore in height. There is nogerm pore orplage, and there is no clear depression around the hilum (the area where the spore was attached to the sterigma). The spores turn an orange-yellow to orange-brown colour inpotassium hydroxide, and turn reddish-brown in Melzer's reagent and in Lugol's iodine, but they are notmetachromatic.[13]
The four-sporedbasidia typically measure 24–35 micrometres (0.00094–0.00138 in) in length by 7–9 micrometres (0.00028–0.00035 in) in width, but can be as much as 10.5 μm wide. They are club-shaped, but narrower in the middle. They arehyaline (translucent) and yellow to yellowish brown. The sterigmata are between 1.6 and 7 μm long.[13] The cheilocystidia (cystidia on the edge of the gill) are typically 30 to 42 (though sometimes as much as 50) μm long by 6–10.5 micrometres (0.00024–0.00041 in) wide. They are shaped like aflask orwine-skin. The top of the cell suddenly widens, and the cell as a whole is thin-walled, hyaline and yellowish, and sometimes appears to contain small grains.[13] The caulocystidia (cystidia on the stem) can be found in tufts at the top of the stem, and measure from 24–60 micrometres (0.00094–0.00236 in) by 3–9 micrometres (0.00012–0.00035 in). They are cylindrical, or narrowly flask-shaped, sometimes with a long neck. They are, again, yellow and hyaline.[3]
The yellowishhyphae are between 15 and 13.5 μm wide with a wall of variable thickness. There areclamp connections at thesepta (the walls dividing individual hypha cells). The flesh in the cap is radial, and is made up of yellowish hyphae of between 2.4 and 20 μm wide. Thepileipellis, the outermost layer of hyphae, forms acutis, and on older specimens (and on the small scales) forms atrichoderm.[3]
There are five species similar in appearance toG. maritimus:G. arenophilus,G. decipiens,G. flavus,G. fulgens andG. pseudofulgens.G. arenophilus and particularlyG. fulgens are the most similar.[16][17] ThoughG. maritimus andG. arenophilus show similarities in theirbiogeography andecology, the typically slightly smallerG. arenophilus differs fromG. maritimusmorphologically. WhileG. maritimus has a cap covered in fibrils with small scales,G. arenophilus can sometimes be completely smooth, and spore ornamentation differs, withG. maritimus typically displaying larger warts.[16] LikeG. maritimus,G. fulgens has been recorded growing on sand-duneheathland; further, the spores are similar in appearance to those ofG. maritimus. However,G. fulgens requires soil rich inpeat and must grow among moss. Moreover, there are a number of morphological differences;G. maritimus mushrooms are larger and thicker, there are never remains of the partial veil onG. fulgens stems, the shape of the top of the spores differs between the two species, and the cheilocystidia and caulocystidia are significantly larger onG. maritimus.G. fulgensvar.luteicystis is even more distinct fromG. maritimus than the nominate variety.[18] Despite the similarities between the three species, the three have been shown to be in differentclades withinGymnopilus, suggesting ecologicalconvergence betweenG. arenophilus andG. maritimus, and morphological convergence betweenG. fulgens andG. maritimus.[11]
Gymnopilus flavus, despite also appearing on land near theMediterranean, can be differentiated fromG. maritimus as it lives among grass, especiallyDactylis glomerata, and it has distinctly smaller spores, typically measuring 5 to 6 by 3.5 to 4.2 μm.[11]G. pseudofulgens, also collected in Italy, shows two major morphological differences: it produces smaller mushrooms, and spores that are of a different shape with smaller warts.G. decipiens, another species that grows on sandy soil, again has spores that are markedly different.[11] The American speciesG. arenicola also favours sandy soil, but has significantly smaller spores thanG. maritimus. Two other species ofGymnopilus found around the Mediterranean areG. corsicus andG. spadiceus.G. corsicus has no veil remnants on the stem, and spores that do not turn red in Melzer's reagent or Lugol's iodine, and so can easily be differentiated fromG. maritimus.G. spadiceus shows several similarities toG. maritimus, but grows only on pine wood and has rectangular spores.[11]
Gymnopils maritimus is clearly a different species from other members of its clade, despite their close relation. All other species in the clade grow upon dead wood and have well-developed rings on their stems. The spores also differ; in the case ofG. junonius andG. spectabilis (often considered synonymous), as well asG. pampeanus, they are narrower, and in the case ofG. imperialis, they are wider. Of the other members of the clade, onlyG. junonius andG. spectabilis also grow in Europe.[11]
Gymnopilus maritimus is known only from a single site inPittulongu, an area ofOlbia, inSardinia, Italy, which is thetype locality. There, mushrooms were found growing in close groups and tufts on coastalsand dunes around 10 metres (33 ft) from thehigh tide line.[3] They were observed at the base of liveJuncus maritimus (sea rush) plants, growing on sandy soil or decaying plants,[3] where they were feeding assaprotrophs. As such, it is possible that the species would be able to grow on othersubstrates.[16] They were observed growing from autumn to winter,[17] between the end of October and January.[3] In addition to the collections in Sardinia, Contu and Vizzini speculate that reports ofG. fulgens growing in "sand-dune heaths" on Great Britain, an unusual habitat for that species, may in fact show the presence ofG. maritimus on the island.[17]
