The Actors

Stomach fungi is a group of mushrooms forming caveties around their spores. The spores are released in the cavety as the fruit-body gradually matures. From there the spores can escape through pores in the inner wall from the fruit-body.
In literature since the seventies it is stated that this group is an artificial, not natural existing taxonomic ordering. Research evidence implicates fungi in this group inherit too many genetic properties of agarics (agaricus, lepiota, and boletales). Anyway, spores in stomach fungi are growing on reproductive cells (basidiomycetes).

Stomach fungi is not a uniform group of inner and outer forms. What they do share is a fertile tissue (gleba), and often an infertile, supporting tissue (subgleba). There might be holes in the supporting tissue, and those holes can be organised single chambered (stiff) or multi chambered (spongy). They might have some kind of inner stem (pseudocolumella).
They have a upper skin (exoperidium) and may have a lower skin (endoperidium). The upper skin may have scales, spines, warts, ridges, fibres, pruina, and so on.
The lower skin may have one or more openings for releasing the spores (pores), and might have very thinly perforations of lost spines or might have warts as remaining parts of the worn outer skin. Earthstars might have cristal pruina or warts on their endoperidium.

Lots of terms (concepts), and adjectives are needed for an adequate description. And metaphors. Many stomach fungi do have a more or less rounded shape. How to name it?
The teacher Math always said "never compare apples with pears!" In mathematics that is correct, but talking about spherical, globose or ovoid fungi it is a must.

Learning fungi is language learning, too.

The Stage

Amongst the stomach fungi group a lot of species prefer poor sandy soil (dunes) under rather rough and extreme conditions (in permanent pioneer vegetations). The original soil of Amsterdam is peat and clay. Soil and vegetation near the city is much more fertile. To find dune species, someone has to go to the Northsea dune coast or to look for city developmental areas, where sea sand is used to raise dikes, (rail-)roads, railway yards, harbours and recreative parks.

Southeast of Amsterdam there is an area, Het Gooi, positioned on a preglacial pleistocene sandhill relict.
Over there is non calcareous, poor sand, partially with woodland (summeroak-birch) and heathland. To find dune species there, you have to go to the borders of the hills, on raised recreation beaches, at the foot of bridges (Hollandse bridge A6, Stichtse bridge A27), on dike bodies of relatively new highways (A27), and to the remaining dune and cliff coast of the former Zuiderzee. Those are places with calcareous sandy soil.

Generally speaking, it is the origin of the sand being used for dikes, railway lines, and other city development, which determinates the chance to find certain species. That sand upto 1960 came from Het Gooi (non calcareous), in the years round 1970 it came from from the Zuiderzee area (calcareous), and from the Gaasperplas (less calcareous), round 1980 from the North Sea (calcareous), and the last years from the fairway Amsterdam-Lelystad (partial calcareous). You just have to know where they used it for.

Within a few years on (won under water) seasand mushrooms are growing. That is an interesting observaton found in the book Champignons in de Jordaan (1999). This book forms the result of a five years long research of mushroom distribution in and around the city of Amsterdam.

Spores of stomach fungi are water-repellent. Even during heavy rains the spores disperse easily. Ask a child to pinch gently in a ripe earthstar or puffball, and see the exaltation in his eyes (and his parents) while a dark brown cloud of spore mass is rizing, contrary to the expectation, against the steady rain fall.

Spores of most other types of mushrooms are attached to each other in the rain. Those (gilled) mushrooms are protecting their spores with an umbrella against water. This is why you must reset a picked mushroom afterwards. Because than it still has a chance to release the spores later.

Earthstar and look alikes are stomach mushrooms. There is some kind of tulip bulb in the ground. It splits open in a number of slips. The slips reveal a little ball. Slips are while curling outwards (and often downwards) pushing up that little ball. The miracle is a fact. A new star is born.
Earthstars and look alikes are divided into Barometer Earthstar (Astraeus), Leather stars (Mycenastrum), and Pepper Pots (Myriostoma).

Geastrum species do have one single, infertile kind of stem (columella), and will get only one pore for releasing the spores. Species with none or with more than one, do not belong to genus Geastrum. Barometer Earthstar (Astraeus hygrometricus) and Leatherstar (Mycenastrum corium) have none, Pepper Pot (Myriostoma coliforme) has many of them.
Counting the number of pores seems to be more efficient, but is not always practical. Young earthstars still have to grow. A lot of their attributes are developing during maturation. Only a few features are there from the very beginning: scars, encrusted debris, some mouth-opening parts.


See: a Macroscopic Key to Earthstars (based on scars).

Puffballs are stomach mushrooms. Puffballs often have a pear shape (so called ´pyriform´). Part of the pear shape has a stem function. In that stem-like part of the pear-shape puffballs do have special tissue to remain erect. It is supporting tissue, with holes in it for strength and elasticity.
Puffballs may have all sorts of typical field attributes: with or without stem, with or without spongy tissue in the stem foot, with or without so called 'roots ' (rhizomorphs), with or without pores (rounded openings at the top for pooring out the spores).
This group of species may be divided into true puffballs, (like Lycoperdon, Calvatia or Handkea, Vascellum genus), bovists (like Bovista, Langermannia genus), stalkballs (Tulostoma genus), and earthballs (Scleroderma genus).
This division again is a bit arbitrary. In some countries they don't split them at all. A reason for splitting them is field recognition.
Real puffballs do have a spongy subgleba, Bovists don't, they are stiff if they have subgleba, and some Bovists do not have subgleba at all. Just feel it, and you know the difference.
Stalkballs have a stalk or stem under there globose form, and often this stem is complete underground.
Earthballs are different from all the others with their thick leatherish skin.

Stinkhorns are stomach fungi. They are easily recognized by its shape and evil smell. They start being eggs in the ground. Even under ground they smell already. Almost all stinkhorns are bound to the presence of certain types of wood, either to moulded wood, either to leaf litter.

Better not to pinch in there, because it smells, and you can't help spreading the spores.

Birds nest fungi are stomach fungi. The spores are formed in an "egg" (peridiole).
Each egg sitting at a small bird's nest, can fly away up to a 5 feet distance.

• Ga 204010 Pestle Puffball (Calvatia, Handkea excipuliformis)
• Ga 204020 Mosaic Puffball (Calvatia, Handkea utriformis)
• Ga 216010 Dusky Puffball (Blackish Puffball) (Lycoperdon foetidum)
• Ga 216040 Soft Puffball (Lycoperdon molle)
• Ga 216050 Common Puffball (Lycoperdon perlatum)
• Ga 216060 Stump Puffball (Lycoperdon pyriforme)
• Ga 216070 Grassland Puffball (Lycoperdon lividum)
• Ga 231010 Meadow Puffball (Vascellum pratense)

• Ga 202030 Least Puffball ( Bovista limosa )
• Ga 202040 Brown Puffball ( Bovista nigrescens )
• Ga 202050 Grey Puffball ( Bovista plumbea )
• Ga 202060 Floury Puffball (l.t. from NL) ( Bovista aestivalis )
• Ga 202070 Dwarf Puffball ( Bovista pusilla )
• Ga 215010 Giant Puffball ( Langermannia gigantea )

Earthballs are compact and heavier than puffballs. They have a rather thick, leatherish skin, around a massive body. That is much thicker and firmer than puffballs. Young they have hard, more or less white meat inside. While maturing the white meat changes into a dark spore mass. If the spores are ripe, the outside wall rips open in quite irregular forms, usually at the top (apex).
Earthball generally are firmly attached to the ground (rhizomorphs), and some species do have a pseudo-stem (also rhizomorphs). Normally they grow on the ground, rarely on wood.
All types of Scleroderma grow in mixed deciduous and coniferous forests, on nutrient-rich land; sandy, loam, clay and peat-land.
They are supposed to form a symbiotic relationship with tree roots.
Most species are autumn species (August till October).

Most species have an outside wall with a scaly structure. The kind of scales, and the scales position are the most important attributes to distinguish species from eath other. For example, Potato earthball's only have scales near the apex, not at the lower parts of the fruit body. That is why they are called baldy. All other species do have scales at the sites and even lower. Even the Leeky earthball, though sparsely only.
While maturing the upperskin can get cracks, and the colors in that cracks help you to find out which of these species is the one.

Scales, skin color, pattern, root length, color change and odor when crabs or cutting, are the main attributes for a Macroscopic Key to earthballs.

• Ga 228010 Leopard Earthball (Scleroderma areolatum)
• Ga 228020 Potato Earthball (Scleroderma bovista)
• Ga 228030 Onion Earthball (Scleroderma cepa)
• Ga 228040 Common Earthball (Scleroderma citrinum)
• Ga 228050 Scaly Earthball (Scleroderma verrucosum)

Stalkballs consist of a globose shape on a long stem or stalk (called stipe). The stipe is formed underground, and is gradually becoming visible when wind and rain are pushing away the surrounding sand.
In the globose shape spores are formed. At maturation a hole in the top of the ball is created, and spores are poored out.

Stalkballs are lime lovers, and that means you need to find them in calcareous land, open grassland, sandy places, with alges and mosses.
They are rare in the Nederlands, but when there are somewhere, they are there gathered together with thousands of them.

Basically, there are three different species. You do not need a macroscopic key for that.

If the pore on the apex has no chimney form, it is a Sessile stalkball (Tulostoma fimbriatum), else if there is a chimney and the stalk is dark, it is a Scaly stalkball (Tulostoma melanocyclum), else if stipe is a bit white till pale brown then you have found a Winter stalkball (Tulostoma brumale).

Stalkballs are found in de Amsterdam region since 1998. Especially in the westport area of Amsterdam.
The Amsterdam westport area was stripped off in 1997 (stripped of top layer plus vegetation). This changed the area into a typical dune habitat (a pioneer vegetation).

The westport area remains promising. It contains a thick suit Northsea sand (very calcareous) on the original marine clay layers.
Elsewhere, sandy soil is becoming enriched in only a few years by tree leaves. That makes the habitat changing fast into some ruderal area with more and more trees and bushes.

Part of the success of the westport area are the rough weather conditions of open areas where the wind can blow and, like in the dunal coast, vegetation is permanently set back to a pioneer environment. Stalkballs love that kind of conditions.

Promising new areas with calcareous sand (from the fairway Amsterdam-Lelystad) are: Diemerzeedijk (or Diemer park), and the new islands of IJburg (one of the newest parts of Amsterdam) built on the former Zuiderzee bottom.