Vaclavy, Czech Republic

• Václavy municipality flag
• Not the Václavy mushrooms

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Václavy municipality flag

The mushrooms shown on the flag of Václavy belong to the genus Armillaria. The genus name has the same origin as the medieval armillary sphere (shown on the national flag of Portugal), the Latin word armilla, bracelet. On the flag, the mushrooms have indeed a ring around the stalk. It must be noted that the representation of the mushrooms is fairly accurate and put me immediatly on the track of Armillaria.

The taxonomy of genus Armillaria  is extremely complicated and disputed. The most famous Armillaria, today believed to be a complex of different species hardly distinguishable, is Armillaria mellea (Vahl ex Fries) Kummer, the honey mushroom. The Latin epithet mellea refers to honey (mel, in French miel), the colour of the mushroom. The mushroom has several local names, for instance, te^te de Méduse (Medusa's head), pivoulade, and souquarel in French; Hallimasch and Honniggelb Ringling in German; chiodini and fonghi del morar in Italian; and pollancrons in Spanish.

The English-Czech index of fungi names lists three species of _Armillaria_:
A. mellea  <--> václavka obecná;
A. ostoyae <--> václavka ostoyova;
A. tabescebs <--> václavka bezprstenná.
The Czech name of  Armillaria is therefore václavka, and the flag is canting the name of the municipality Václavy.

The václavka / Armillaria fungus is a threat to forests, and also orchards and vineyards. The part of the fungus seen on the flag represents its fruiting body (carpophore), but its dangerous part lies underground. Like most mushrooms, the honey fungus spreads via a mycelium (what is usually called the "roots" of the mushroom, but is not).  However, the honey fungus develops two kinds of mycelium:
- a blade-shape mycelium, which grows into the bark and the wood of the tree and then invades the root system;
- an underground mycelium made of bootlace-like strings called rhizomorphs (lit., root-shaped), which grow around infected trees and contaminate the neighnouring healthy trees. The rhizomorphs are also a means of conservation of the fungus when climatic conditions are not conducive to fruiting.
When a tree is attaked, the first damage  is a rapid rotting of the roots. Accordingly, tyhe hydric and mineral alimentation of the tree is suppressed, causing the death of the tree. Due to the spread of disease via the rizomorphs, dead trees are grouped in circles called in France ronds. In English they are named fairy circles.

A survey of A. ostoyae in a stand of 110-year-old Douglas firs in British Columbia (Canada) showed that the disease progressed at a rate of 22 cm per year between 1989 and 1992. The average time from first appearance of symptoms to tree death was 6 years. Small trees died more quickly than large ones (van den Kamp, B. 1993. Rate of spread of
Armillaria ostoyae in the central interior of British Columbia.
Source: Canadian Journal of Forest Research, 23, 1239-1242).

In 1992, an "individual" of Armillaria bulbosa  sampled in a northern Michigan hardwood forest was elected one of the largest and oldest living organisms. Genetic studies showed unambiguously that  the clonal individual (that is a fungus which grew only by the way of rhizomorphs and without any sexual reproduction) occupied at least 15 hectares, weighs in excess of 10,000 kg and has remained genetically stable for more than 1,500 years (Smith, M.L., Bruhn, J.N., Anderson, J.B. 1992.
The fungus Armillaria bulbosa is among the largest and oldest living organisms. Nature 356, 428-431).

An even largest honey fungus, covering 600 hectares, was found in the state of Washington. This latter record was beaten in August 2000, when massive forest dieback in the Blue Mountains of Oregon was linked to a 2,400-yer-old fungus occupying at least  890 hectares. The extreme growth of the fungus was probably allowed by dry weather conditions, which were not conducive to the estabishment of competing species via spores.
The story of the new record holder, with pictures, can be read on the Extreme Science E-zine.

The honey fungus mostly attacks tree stands in poor growth conditions. There is no chemical control available, although poisoning the contaminated stumps might reduce the risk of further spread of disease.
The honey fungus is considered as a low value fungus by the mycogastronoms. The fungus must be cooked for a very long period to suppress bitterness. A limited number of poisoning cases have been reported following massive ingestion of honey mushrooms. The fresh mushroom is said to smell like a Camembert cheese.
Ivan Sache, 6 Jul 2004

But why Armillaria = "vaclavka"? That's elementary, my dear mycovexillologist: Vaclav = Venceslaus, St. Venceslaus (a medieval Bohemian duke) Day is 28 September, and Armillaria is a typically autumn-fructifying fungus.
Jan Zrzavy, 7 Jul 2004

A spring - and very edible - version of the St. Venceslaus' fungus is the meadow mushroom Lyophyllum georgii,  a.k.a. (at least in French) St. George's mushroom. St. George's day is 23 April.
The common name of St. George's mushroom is mousseron, which probably gave the English word mushroom.
St . George's mushroom grows on football fields, especially near David Beckham's penalty point.
Ivan Sache, 7 Jul 2004

Not the Václavy mushrooms

I am attaching to this message an image of a group of Armillaria carpophores, snapped from the Extreme Science website. I have labelled the image <cz_hon.jpg> for the sake of consistency but the picture was probably not taken in Czech Republic. It seems that the black dot shown on the fungus stalk on the flag are supposed to represent the scales which stay around the stalk of the adult carpophore, once the veil surrounding the young "egg" has been destroyed.
Ivan Sache, 6 Jul 2004