Velum (mycology)

The velum (German shell ) is the meshwork of the fruiting bodies of some mushrooms . The vela can be pronounced as a membrane , which tears open when the fruiting body is stretched, but can also be significantly reduced, for example spider web- like. A distinction is made between the Velum universale (total envelope), which can cover the entire fruiting body and consists of two sub-plexuses, the Pileoblem and the Cauloblem, and the Velum partiale (partial envelope), which only covers the fruit layer of young fruiting bodies. Structures produced by the Vela are e.g. B. Ribbons on the stem, stem rings , skin remnants or flakes on the hat or a volva on the stem base. Velum structures or velum remains are very important macroscopic features for differentiating between fungal species.

Velum universale (entire envelope)

The Velum universale consists of two sub-braids, the Pileoblem and the Cauloblem. The Pileoblem is on the hat, but can reach over the edge of the hat and also run down a little on the stem. The cauloblem begins at the base of the stem and envelops the stem on which it rises. Pileoblem and cauloblem merge to form a uniformly appearing Velum universale or they slide over each other at the point of contact. For example, in Hallimasch species (genus Armillaria ), remnants of the pileoblem in the form of small, dark brown flakes can be seen on the cauloblem.

The Velum universale produces - depending on the mushroom species or genus - a volva at the base of the stem, so-called velum bands on the stem, ascending or freely movable rings on the stem (often together with the Velum partiale), remnants of shell on the hat (e.g. B. the white flakes on the hat of the toadstool). The pile oblem as part of the Velum universale can, however, also grow together completely with the surface of the hat and thus form a hat cover layer that is no longer recognizable as a velum structure. The final braid of the hat of the spotted- leaved scarfling ( Gymnopilus penetrans ), for example, is a reduced and completely overgrown pileoblem. The cauloblem, on the other hand, is still clearly pronounced and creates conspicuous velum structures on the stem surface of this species.

Velum partiale (partial cover)

The Velum partiale consists only of the Lipsanoblem. It extends from the tip of the handle or from the upper area of the handle to the edge of the hat. Often the velum is partially reduced and threadlike like a cobweb. It is also known as Cortina in this case.

Nomenclature of fruiting body development according to the presence of the vela

Fruit bodies that have no vela are called gymnocarpic fruiting bodies or this form of fruiting body development is called gymnocarpy .

If only the velum universale occurs, but no velum partiale or no lipsanoblem, this is called monovelangiocarpy . An example of this would be the ringed earth knight ( Tricholoma cingulatum ). The term hypovelangiocarpy is used for the special case that the Velum universale is only detectable in the primordium (the fruiting body structure) and then disappears in further development .

If only the velum partiale (or the Lipsanoblem) occurs, the development of the fruiting body is called paravelangiocarpy . It should be noted, however, that, strictly speaking, the Velum universale is also present here, is only very inconspicuous and therefore hardly appears. The term is also used when the formation of a stem ring is still unclear, but there are no (noticeable) traces of a Velum universale.

If both the Velum universale and the Velum partiale occur, the term bivelangiocarpy is used. An example of this would be the amanita (genus Amanita ). In the special case that the two vela are only detectable at the primordium and then disappear completely, the term metavelangiocarpy is used.

Recognizing the velum structures

The exact classification of the type of fruiting body development is often not possible purely macroscopically. The ascending ring of the Amiant granular umbrella ( Cystoderma amianthinum ) appears macroscopically as a pure formation of the Velum universale, while the inside of the protruding part of the ring is a formation of the Velum partiale or the Lipsanoblems, which here is the Velum universale is completely merged. So there are both vela.

Apparently gymnocarpic mushroom species can also have vela. In the cherry-red Spei-Täubling ( Russula emetica ), both the caulo and the pileoblem are present, only very much reduced and anatomically detectable on the very young fruiting body as a coherent layer of vertically protruding gloeocystids. The collar swindler ( Marasmius rotula ) is called gymnocarp or paravelangiocarp, depending on the author. However, studies of primordial dienontogeny show that the collar dodger is surrounded by a total envelope. It grows together on the hat with the hat meat and forms the later hat skin of the mushroom fruit body. Hence it appears as a seemingly gymnocarp.

In representatives of the umbrella flies (genus Lepiota ) one recognizes velum bands on the stem in many species. So z. B. in woolly pussed umbrella ( Lepiota clypeolaria ). On the hat, however, the velum universale is firmly fused with the actual hat cover layer, but is also present there. The Lipsanoblem here is rather inconspicuous and pronounced like a cobweb, but also present.

ring

The ring, also known as a cuff, can be formed either only from the velum partiale or only from the velum universale, but also from both vela together. In the Hallimasch iw S. all three partial structures (Pileo, Caulo and Lipsanoblem), i.e. both the Velum universale and the Velum partiale, are involved in the ring. The Lipsanoblem and the Cauloblem form the ring structure per se, the Pileoblem also forms fine, brownish to brown flakes on the ring.

In many mushroom species or genera, the vela grow together, especially when the cauloblem is in contact with the stem. Is the velum but universal an outgoing already at the stem base from the edge of a tuber, membranous structure such as in species of the genus Amanita ( Amanita ), the velum are universal and the velum offers partial usually very clearly separated. Here then only the velum partiale forms the ring of the stem.

Velum universale; the Velum partiale is not recognizable here because it is located within the Velum universale.
The thick, complex ring is formed here from the Velum universale and the Velum partiale together.
The young fruiting body of an orange-yellow streifling breaks out of an all-encompassing Velum universale
Remnants of a Velum universale on the hat of an orange-yellow streifling
The fly agaric shows the remains of a Velum partiale (the ring) and a Velum universale (the dots)

literature

Heinrich Dörfelt , Gottfried Jetschke (Hrsg.): Dictionary of mycology . 2nd Edition. Spectrum, Heidelberg 2001, ISBN 3-8274-0920-9 , p. 336-338 .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Heinz Clemençon: Large mushrooms in the microscope . In: Supplement to the journal for mycology . tape 12 , 2012, p. 1-176 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p Heinz Clemençon: Anatomy of the Hymenomycetes . F. Flück-Wirth, Teufen 1997, p. 1-996 .

Web links

Commons : Velum (Mycology) - Collection of images, videos and audio files

[:0-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Heinz Clemençon: Large mushrooms in the microscope . In: Supplement to the journal for mycology . tape 12 , 2012, p. 1-176 .

[:1-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p Heinz Clemençon: Anatomy of the Hymenomycetes . F. Flück-Wirth, Teufen 1997, p. 1-996 .