Olive-brown snail

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Olive-brown snail
Olive-brown snail (Hygrophorus olivaceoalbus)

Olive-brown snail ( Hygrophorus olivaceoalbus )

Systematics
Class : Agaricomycetes
Subclass : Agaricomycetidae
Order : Mushroom-like (Agaricales)
Family : Snail relatives (Hygrophoraceae)
Genre : Snail ( hygrophorus )
Type : Olive-brown snail
Scientific name
Hygrophorus olivaceoalbus
( Fr. ) Fr.

The olive-brown Schneck Ling ( Hygrophorus olivaceoalbus ), also Natternstieliger Schneck Ling called, is a fungus of the genus of Hygrophorus . It appears from August to November under conifers in mountain forests of North America and Eurasia and can be recognized by its olive-brown hat and elongated stem. In addition to its use as an edible mushroom , it has gained in importance, especially due to the recently discovered antibiotic ingredients.

features

Fruiting bodies

The hat of the olive-brown snail is 2–12 cm wide and hemispherical in young mushrooms; with age it becomes flatter and wider, but retains its characteristic dark hump. The surface of the gray to sooty brown hat is slimy and has a veiny appearance due to the overstretched hat fibers under the mucous layer. The edge is initially inflected, but becomes more protruding with age. Young fruiting bodies are covered by two layers of velum , with the inner velum often remaining as a dark ring .
The mushroom has an elongated, slender and full stem with a length of up to 15 cm, a diameter of 1–3 cm and a surface that is slimy when the weather is damp. It is white underground and often with an olive-brown color ; its tip, on the other hand, is whitish and moist. The stem is usually narrower at the base. The stem is covered by two layers of tissue: the outer one is sticky, the inner one is relatively thin and consists of flaky fibers, similar to those under the mucous layer of the hat, with which they are initially connected. As the stalk grows in length, the lower layer tears, creating snake. The narrow lamellae of the olive-brown snail are plump and run down the stem; they are white, slightly greyish at the base, and have a waxy surface.

The hats and stems of the olive-brown snail are slimy coated.

The flesh of the mushroom is soft, thin, and white. It tastes mild and has no distinct odor; however, it reacts reddishly with sodium hydroxide and sulfuric acid . The olive-brown snail's spore print is also white.

There is a possibility of confusion with numerous other, often closely related species, which taxonomically cannot be clearly distinguished from H. olivaceoalbus . For example H. pustulatus , H. inocybiformis , H. tephroleucus or H. morrisii (see also section Systematics ). In case of doubt, the olive-brown snail can only be determined by checking all its specifics, above all the double velum and the snaking of the stem, as well as the microscopic properties . However, there is no danger of mistaking it for poisonous mushrooms.

Microscopic properties

The fungal spores have a size of 9–12 × 5–6  µm , are elliptical in shape and are not amyloid ; their surface is smooth. Melzer's reagent turns it yellow. The 46–62 × 7–10 micrometer large basidia are four-pore and have short, sturdy sterigmata . Neither pleuro cystids nor cheilocystids are present.

The gelatinous cuticle has a thickness of 250 to 450 micrometers and consists of loop-shaped, dark hyphae with a width of 2 to 3 micrometers, which, arranged horizontally, form an ixocutis and have buckles ; The fungus does not have a hypocutis. The trama of the hat consists of radially extending hyphae, that of the lamellae of branched hyphae about 3–8 µm thick.

Mycorrhiza formed by the olive-brown snail as a fungal partner , such as the spruce mycorrhiza Piceirhiza gelatinosa , is white and has a smooth, waxy surface under which hyphae lie in several layers around the roots of the tree; Sometimes this mycorrhiza shows hypertrophy . The hyphae are encased in a gelatinous mass that is secreted by the outer walls of the hyphae.

Ecology and diffusion

Spruce forests in monoculture form a preferred habitat for the fungus

The olive-brown snail forms mycorrhiza with a number of conifers. While it can be found almost exclusively under spruce and rarely under pines in northern Germany , it populates the ground under fir trees in the Pacific Northwest , while Sitka spruce and coastal sequoia trees on the west coast . In the Rocky Mountains , he settled Engelmann spruce , on the north east coast of the USA hemlock . As a rule, it prefers acidic and calcareous soils with moss growth in higher altitudes and coniferous forests, but can also be found under isolated conifers in the deciduous forest .

The distribution area of ​​the olive-brown snail is Holarctic and extends over the north and west coast of the North American continent as well as all of Europe (with the exception of the Mediterranean region) and Russia. In Germany it can be found almost everywhere, although less often in the North German lowlands than in the low mountain ranges . It appears mainly between August and November, but sometimes (depending on the geographical location and climate) it can also be found in June or well into December. The population is apparently not at risk at the moment; the olive-brown snail is not on the red lists of Switzerland, Germany and Austria.

Systematics

The systematic position of the olive-brown snail, as with many other large mushrooms, is not fully understood. The differentiation from other Hygrophorus species and the classification of the subtaxa are particularly difficult .

External system

H. olivaceoalbus is very similar to other closely related snails. The olive-booted snail ( H. personii ) is regarded by some authors as a synonym for H. olivaceoalbus . What is noteworthy in this context, however, is the fact that H. personii and H. olivaceoalbus produce different mycosterols ( sterols , see also in the Pharmacology section ) and their meat reacts differently to the addition of NaOH (red for H. olivaceoalbus compared to olive green for H. personii ). In addition, H. personii prefers oaks as mycorrhizal partners. Together with the black- dotted snail ( H. pustulatus ), the olive-puss, the gray-brown slime- stemmed snail ( H. mesotephrus ) and the white- scaly puss ( H. latitabundus ), the olive-brown snail forms the section Olivaceoumbrini within the genus Hygrophorus . The representatives of this section have greasy to slimy hats and stems. Their hats are dark brown-gray, olive or orange. The stalk is latticed or more or less clearly ringed.

Internal system

The internal classification of H. olivaceoalbus is a complex procedure: while some varieties in the shape of their fruiting bodies and their microscopic characteristics nominate are very similar, showing H. olivaceoalbus var. Gracilis a much smaller and partly differently shaped fruiting bodies, but it is due the surface texture of its fruiting body counted as a variety.

The following varieties have been described for the olive-brown snail :

variety Initial description comment
var. olivaceoalbus ( Fr. ) Fr. (1883) Nominate form
var. intermedius Hesler & AH Sm. (1963) Spores react hyaline with KOH . Under Engelmann spruces in Colorado .
var. gracilis Maire (1933) According to the initial description, smaller spores (9–13 × 6–6.5 micrometers) and especially in dark, mossy areas under deciduous trees in Spain. However, Hesler and Smith speak of smaller fruiting bodies and larger spores than in the nominate form (10–14 × 5.5–7.5 micrometers); Hyphae of the cuticle react dark brown with Melzer's reagent. According to Hesler and Smith, under fir trees in Oregon, Washington, Michigan, and British Columbia.

meaning

Edible mushroom

The olive-brown snail is mainly used in the kitchen, although there are positive as well as negative statements about its food value. The latter are usually justified with the laborious removal of the slimy skin; In the mushroom literature, meat is on the one hand given a bad taste, on the other hand it is referred to as a good edible mushroom. The popularity of this snail varies from region to region. In Europe it is used more often than in North America for mushroom dishes, and it is also in different demand within Europe. In Spain, for example, it is only considered tasty in Catalonia, although mushroom dishes are more common in this region than in the rest of Spain.

Cyclopentenone derivatives, isolated from Hygrophorus olivaceoalbus or their semisynthetic acetyl derivatives, with R 1 , R 2 and R 3 = H or Ac and n = 14 or 16

pharmacology

Cyclopentenone derivatives, the so-called hygrophorones , which the fungus produce as secondary substances , can be obtained from the fruiting bodies of the olive-brown snail . The compounds found are polyols and have antifungal and antibacterial (i.e., fungus and bacteria-fighting) effects, particularly with respect to Gram-positive bacteria . The olive-brown snail thus plays an important role as a supplier of antibiotics , all the more since the hygrophorones also have an effect on bacterial strains that are resistant to common antibiotics such as methicillin , ciprofloxacin or vancomycin .

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literature

Web links

Commons : Olive-brown snail ( Hygrophorus olivaceoalbus )  - album with pictures, videos and audio files

Individual evidence

  1. ^ A b David Arora: Mushrooms demystified: a comprehensive guide to the fleshy fungi. Ten Speed ​​Press, 1986, ISBN 0-89815-169-4 , pp. 127-128.
  2. ↑ a b c Hans E. Laux: Edible mushrooms and their poisonous doppelgangers . Franckh'sche Verlagshandlung, W. Keller & Co., Stuttgart 1985, p. 44.
  3. ↑ a b c d e Michael Kuo: Hygrophorus olivaceoalbus www.mushroomexpert.com, January 2007. Retrieved October 4, 2009.
  4. ↑ a b c d e L. R. Hesler , Alexander H. Smith : North American species of Hygrophorus. University of Tennessee Press, Knoxville 1963, pp. 291-294.
  5. ^ LR Hesler, Alexander H. Smith: North American species of Hygrophorus. University of Tennessee Press, Knoxville 1963, p. 288.
  6. ↑ Ingeborg Haug: Identification of Picea-ectomycorrhizae by comparing DNA sequences. In: Mycological Progress . Vol. 1, No. 2, May 2002, pp. 167-178. doi: 10.1007 / s11557-006-0016-9
  7. ^ JR Norris, DJ Read, AK Varma: Techniques for the study of mycorrhiza 23rd Academic Press, 1991, ISBN 0-12-521523-1 , p. 49 f.
  8. ^ A b Hermann Jahn : Distribution and locations of the snails, Hygrophorus, in Westphalia. (PDF; 752 kB). P. 64.
  9. ↑ Jean-Paul Koune: Threatened mushrooms in Europe, Issue 18 Council of Europe, 2001, ISBN 92-871-4666-7 , pp 52nd
  10. ^ Tilo Lübken: Hygrophorone. New antifungal cyclopentenone derivatives from Hygrophorus species (Basidiomycetes). (PDF; 3.3 MB). 2006, pp. 118-119.
  11. ↑ Tilo Lübken et al: Hygrophorones AG: fungicidal cyclopentenones from Hygrophorus species (Basidiomycetes). In: Phytochemistry Volume 65, Number 8, April 2004, pp. 1061-1071.
  12. ↑ Index Fungorum.Retrieved September 2, 2009.
  13. ^ Vera B. McKnight, Roger Tory Peterson: A Field Guide to Mushrooms: North America. Houghton Mifflin Harcourt, 1998, ISBN 0-395-91090-0 , p. 288.
  14. ^ M. de Román, E. Boa: Collection, Marketing and Cultivation of Edible Fungi in Spain. (PDF; 143 kB). In: Mycología Aplicada International . Volume 16, No. 2, July 2004, pp. 25-33.
  15. ^ Tilo Lübken: Hygrophorone. New antifungal cyclopentenone derivatives from Hygrophorus species (Basidiomycetes). (PDF; 3.3 MB). 2006, p. 28.
  16. ^ Tilo Lübken: Hygrophorone. New antifungal cyclopentenone derivatives from Hygrophorus species (Basidiomycetes). (PDF; 3.3 MB). 2006, p. 5.
This version was added to the list of articles worth reading on October 25, 2009 .