Indigo charm

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Indigo charm
Lactarius indigo 48568 edit.jpg

Indigo irritant ( Lactarius indigo )

Systematics
Subclass : insecure position (incertae sedis)
Order : Russulales (Russulales)
Family : Deaf relatives (Russulaceae)
Genre : Milklings ( Lactarius )
Section : Irritant ( Deliciosi )
Type : Indigo charm
Scientific name
Lactarius indigo
( Pig. ) Fr.

The Lactarius indigo ( Lactarius indigo ) is a fungal art from the family of Täublingsverwandten . The Milchling is widespread in eastern North America, Central America, and East Asia. From Europe only occurrences in southern France are known so far. The fungus grows in both deciduous and coniferous forests , where it forms mycorrhizae with various tree species. The color ranges from dark blue in young specimens to a pale blue-gray in older fruiting bodies . The indigo-blue milk that escapes when the flesh is damaged turns green when it comes into contact with air. The hat typically measures 5 to 15 cm in diameter, the stem is 2 to 8 cm high and 1 to 2.5 cm thick. The mushroom is edible and is available at farmers' markets in Mexico , Guatemala, and China .

features

Macroscopic features

Indigo charm from Guadalajara , Mexico with concentrically zoned hats

The cap of the fruiting body is 5-15 cm wide, initially convex and gradually develops a flat funnel shape. With age it becomes even more depressed, with the edge bulging upwards. When young, the brim of the hat is rolled inwards, but unfolds and rises as the mushroom grows. In young specimens the hat is indigo blue, but in old mushrooms it becomes gray-blue or silver-blue, sometimes with greenish spots. It is often zoned in a ring with dark blue spots towards the edge of the hat. The caps of young specimens have a sticky surface.

Freshly cut fruit bodies show a blue flesh.

The flesh is pale bluish and slowly turns green on contact with air; its taste is mild to slightly bitter. The flesh of the entire mushroom is brittle, and the stem breaks cleanly when bent. The milk that emerges from the injuries is also indigo blue and gives the section a greenish tint; like the meat, it tastes mild. Lactarius indigo is notorious for not producing as much milk as other Lactarius species and especially old specimens can be so dehydrated that they no longer secrete milk.

The brim of the hat is rolled inwards in young specimens.

The lamellas are attached to the stem or slightly curved and are densely packed. Their color ranges from indigo blue when they are young to a pale gray-blue with age; green spots appear when damaged. The stem is 2-6 cm high and 1.2.5 cm thick, the diameter is the same over the entire stem or sometimes a little smaller at the base. The stem is also colored indigo to silver and gray-blue. The inside of the stem is initially firm and compact, but it often becomes hollow with age. Like the hat, it is sticky or slimy at first, but dries off later. Usually the hat is attached centrally to the stem, but it can also be shifted off-center. The fruiting bodies of the indigo irritant have no special odor.

Lactarius indigo var. Diminutivus (the "Kleine Indigo-Reizker", Engl .: smaller indigo milk cap ), a smaller subspecies with hats 3-7 cm in diameter and stem heights of 1.5-4 cm, is often found in Virginia. Helser and Smith, who were the first to describe the subspecies, remark as a typical habitat: "along the edges of muddy ditches under grasses and herbs with incense pines nearby (along [the] sides of a muddy ditch under grasses and weeds, [with] loblolly pine nearby). "

Microscopic features

The spore print is cream-colored to yellow. When viewed under the light microscope , the spores are transparent ( hyaline ), they are elliptical to almost round with amyloid warts and have dimensions of about 7–9 by 5.5–7.5 µm. The scanning electron microscopy shows Runzelkörner on the surface of the spores. The hymenium is the spore-producing tissue of the fruiting body and consists of hyphae that expand towards the lamellae. Different types of cells have been found in the hymenium and the cells have microscopic properties that can be used to identify or differentiate between species if the macroscopic features are not clear. The spore-bearing cells, the basidia , each have four spores and measure 37–45 µm in length by 8–10 µm in width. So-called cystids are the end cells of the hyphae in the hymenium, which do not produce spores, but serve to spread the spores and ensure the necessary moisture around developing spores. The pleurocystids are cystids that are found on the lamellae themselves; they measure 40–56 by 6.4–8 µm, are roughly spindle-shaped and have constricted tips. The cheilocystids on the edges of the lamellae are common and measure 40–45.6 by 5.6–7.2 µm.

Distribution and ecology

About two dozen blue fruiting bodies of various sizes on a plate.
A collection of L. indigo from Jalisco , Mexico

The indigo irritant is common in southern and eastern North America and is common along the Gulf of Mexico and in Mexico. Its distribution in the Appalachians of the United States has been described as "occasional to locally common". Arora writes that the species is found in the United States in yellow pines in Arizona , but is absent in California's yellow pine forests. The species has also been found in oak forests in China, India , Bhutan , Colombia , Guatemala, and Costa Rica . A study on the seasonal occurrence of L. indigo in the subtropical forests of Xalapa / Mexico showed that the maximum production of fruiting bodies coincides with the rainy season from June to September.

L. indigo forms mycorrhizae and therefore enters into a symbiosis with the roots of different tree species , whereby the fungus exchanges minerals and amino acids from the soil for fixed carbon with the host tree. The subterranean hyphae of the fungus create a network of cell tissue, the so-called ectomycorrhizum, around the roots of the tree - a close mutual relationship that is particularly advantageous for the host, as the fungus produces enzymes that mineralize organic compounds and thus the transport of Allow nutrients to the tree.

Due to their close symbiosis with trees, the fruiting bodies of the indigo irritant are typically found on the ground, scattered or in groups, in both deciduous and coniferous forests . The fungus is also often found in floodplains that have recently been flooded. In Mexico, communities with Mexican alder ( Alnus jorullensis ), American hornbeam , Virginian hop beech ( Ostrya virginiana ) and sweetgum trees have been observed, while in Guatemala the fungus grows on Pinus pseudostrobus and other pine and oak species. In Costa Rica the Indigo-Reizker forms connections with different oak species. Under controlled laboratory conditions it could be shown that L. indigo forms connections with the neotropical pine species Mexican white pine , Pinus hartwegii , Pinus oocarpa , Pinus pseudostrobus and also with Eurasian species such as Aleppo pine , black pine , maritime pine and Scots pine .

meaning

Food value

The indigo is known as an edible species, but opinions differ about its nutritional value: The American mycologist David Arora calls it "excellent (superior edible)", while an identification book for mushrooms in Kansas gives it "medium quality (mediocre in quality) ”. It can taste slightly bitter or peppery and has a coarse, grainy texture . The firm pulp is best prepared by cutting the mushroom into thin slices. When cooked, the blue color disappears and the mushroom turns gray. Because of the grainy flesh, the mushroom is not easy to dry. Specimens with a particularly abundant milk content are suitable for coloring marinades .

In Mexico, wild indigo peas are typically collected for sale from June to November, being considered a second choice edible mushroom. The indigo stimulant is also offered in Guatemala from May to October in markets. It is one of 13 Lactarius varieties sold in Yunnan , southwest China.

Chemical composition

Structure of (7-isopropenyl-4-methylazulen-1-yl) methyl stearate
(7-Isopropenyl-4-methylazulen-1-yl) -methylstearate, the blue, lipophilic azulene pigment of L. indigo . The part of the molecule responsible for the color ( chromophore ) is highlighted in blue.

A chemical analysis of Mexican specimens showed that L. indigo contains 95.1% moisture, 4.3 mg fat per gram of mass and 13.4 mg protein . It contains 18.7 mg of fiber , much more than z. B. in the cultivated mushroom , which contains only 6.6 mg. Compared to three other wild mushroom species that were also examined in this study ( pearl mushroom , Boletus frostii and Ramaria flava ), the indigo irritant had the highest content of saturated fatty acids , including stearic acid - slightly more at 32.1 mg / g than half of the total free fatty acid content.

The blue color of indigo Reizkers is the azulene - derivative (7-isopropenyl-4-methyl azulene-1-yl) -methylstearat caused. The molecule is only found in indigo irritant, but is similar to a compound found in noble irritant .

Taxonomy and naming

Described as Agaricus indigo by the American mycologist Lewis David von Schweinitz in 1822 , the species was assigned to the genus Lactarius in 1838 by the Swede Elias Magnus Fries . The German botanist Otto Kuntze named the species Lactifluus indigo in his publication Revisio Generum Plantarum from 1891 , but this name change was not taken up by other authors. In their 1960 study of the North American species of Lactarius , Hesler and Smith defined L. indigo as a type species of the subdivision Caerulei , a group characterized by blue milk and a sticky blue hat. In 1979 they withdrew their opinion on the subdivisions of the species Lactarius and instead assigned L. indigo to the subgenus Lactarius , based on the color of the milk and its change in color that could be observed on contact with air. They explain:

"The gradual development of blue to purple pigmentation as you move from species to species is an interesting phenomenon that needs further research. It culminates in L. indigo , which is blue through and through. L. chelidonium and its Variants chelidonioides , L. paradoxus , and L. hemicyaneus can be seen as milestones on the way to L. indigo . (The gradual development of blue to violet pigmentation as one progresses from species to species is an interesting phenomenon deserving further study. The climax is reached in L. indigo which is blue throughout. L. chelidonium and its variety chelidonioides , L. paradoxus , and L. hemicyaneus may be considered as mileposts along the road to L. indigo .) "

The species name indigo refers to the Latin name for "indigo blue".

Species delimitation

The characteristic blue color of the fruit body and milk make this species easy to identify. Other species of blue-colored Lactarius include L. paradoxus from eastern North America, which has a grayish-blue cap when young but has reddish-brown to purple lamellas and milk. L. chelidonium has a yellowish to gray-blue cap and yellow-brown milk. L. quieticolor has a reddish-gray to cinnamon-brown hat with blue flesh and orange flesh in the base of the stem. Although the blue color of L. indigo is considered rare within the genus Lactarius , five new species with bluish milk or bluish flesh were found on the Malay Peninsula in 2007 : Lactarius cyanescens , L. lazulinus , L. mirabilis and two as yet unnamed species.

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literature

  • LR Hesler, AH Smith: North American Species of Lactarius . The University of Michigan Press, Michigan 1979, ISBN 0-472-08440-2 .
  • David Arora: Mushrooms Demystified: a Comprehensive Guide to the Fleshy Fungi . Ten Speed ​​Press, Berkeley / California 1986, ISBN 0-89815-169-4 (American English).

Individual evidence

  1. ↑ a b Marcel Bon: Parey's book of mushrooms . Paul Parey, Hamburg, Berlin 1988, ISBN 3-490-19818-2 , pp. 88 .
  2. ↑ Tom Volk: Tom Volk's Fungus of the Month for June 2000 . Department of Biology, University of Wisconsin-La Crosse. 2000. Retrieved January 4, 2011.
  3. ^ A b Susan Metzler, Van Metzler: Texas Mushrooms: A Field Guide . University of Texas Press, 1992, ISBN 978-0-292-75125-5 ( limited preview in Google Book Search).
  4. ↑ Orson K. Miller, Hope Miller: North American mushrooms: a field guide to edible and inedible fungi . Falcon Press, 2006, ISBN 978-0-7627-3109-1 .
  5. ^ Hesler and Smith (1979), p. 86.
  6. ↑ a b L. Montoya, VM Bandala: Additional new records on Lactarius from Mexico . In: Mycotaxon . tape 57 , 1996, ISSN  0093-4666 , pp. 425-450 .
  7. ↑ toilet Roody: Mushrooms of West Virginia and the Central Appalachians . University Press of Kentucky, Lexington, Kentucky 2003, ISBN 0-8131-9039-8 , pp. 93 ( limited preview in Google Book search).
  8. ↑ Arora, p. 35.
  9. ^ S. Chacon, G. Guzmán: Observations on the phenology of ten fungal species in the subtropical forests at Xalapa, Mexico . In: Mycological Research . tape 99 , no. 1 , 1995, p. 54-56 , doi : 10.1016 / S0953-7562 (09) 80316-X .
  10. ↑ G. Diaz, R. Flores, M. Honrubia: Lactarius indigo and L. deliciosus form mycorrhizae with Eurasian or Neotropical Pinus species . In: Sydowia . tape 59 , no. 1 , 2007, ISSN  0082-0598 , p. 32-45 .
  11. ↑ a b Arora, p. 69.
  12. ↑ D. Abel, B. Horn, R. Kay: A Guide to Kansas Mushrooms . University Press of Kansas, Lawrence 1993, ISBN 0-7006-0571-1 , pp. 63 .
  13. ↑ VM Bandala, L. Montoya, IH Chapela: Wild edible mushooms in Mexico: A challenge and opportunity for sustainable development . In: ME Palm, IH Chapela (Eds.): Mycology in Sustainable Development: Expanding Concepts, Vanishing Borders . Parkway Publishers, 1997, ISBN 978-1-887905-01-5 , pp. 62 ( Google Books ).
  14. ^ MF León-Guzmán, I. Silva, MG López: Proximate chemical composition, free amino acid contents, and free fatty acid contents of some wild edible mushrooms from Querétaro, México . In: Journal of Agricultural and Food Chemistry . tape 45 , no. 11 , 1997, ISSN  0021-8561 , p. 4329-4332 , doi : 10.1021 / jf970640u .
  15. ↑ AD Harmon, KH Weis Graber, U. Weiss: Preformed azulene pigments of Lactarius indigo (. Sr.) Fries (Russulaceae, Basidiomycetes) . In: Cellular and Molecular Life Sciences . tape 36 , 1 pages = 54-56, 1979, ISSN  1420-682X , doi : 10.1007 / BF02003967 .
  16. ^ Lewis David von Schweinitz: Synopsis fungorum Carolinae superioris . In: Writings of the natural research society in Leipzig . tape 1 , 1822, p. 87 .
  17. ↑ CE Otto Kuntze: Revisio Generum Plantarum . 1891, p. 857 .
  18. ^ LR Hesler, AH Smith: Studies on Lactarius - I: The North American Species of Section Lactarius . In: Brittonia . tape 12 , 1960, ISSN  0007-196X , pp. 119-39 , doi : 10.2307 / 2805213 .
  19. ^ Hesler and Smith (1979), p. 66.
  20. ↑ Hesler and Smith (1979), p. 7.

Web links

Commons : Indigo-Reizker ( Lactarius indigo )  - Collection of pictures, videos and audio files