Support MycoNote →

MycoNote

Hymenophore

Chambered

Chambered — mushrooms with the trait «Chambered»

When you examine a mushroom's spore-bearing surface, sometimes you simply can't find it on the outside. If a mushroom looks like a ball, a potato or a strange egg with no gills or tubes, you're looking at a member of the group with a chambered hymenophore, whose spore-bearing part is called the gleba.

21 species in the database.

The anatomy and evolutionary meaning of the gleba

A chambered hymenophore differs fundamentally from all other types in that it is completely enclosed inside the fruiting body (angiocarpic development). M.Ya. Zerova explains in «Key to the Fungi of Ukraine» that in these mushrooms the hymenium lines internal cavities (chambers). As they mature, the tissue inside these chambers breaks down, turning into a dry spore mass (as in puffballs) or a slimy mass (as in stinkhorns).

David Arora in «Mushrooms Demystified» groups these mushrooms under the general (though taxonomically outdated) term "Gasteromycetes" — literally "stomach fungi." The evolutionary strategy of the chambered hymenophore is to protect the spores from the outside environment as much as possible while they form.

Roger Phillips in his guide «Mushrooms» details the different strategies for spreading spores from the gleba:

- In puffballs (Lycoperdon) and bovists, the outer skin eventually forms an opening, and the spores are puffed out as "smoke" when raindrops or animals hit it.

- In truffles (Tuber), which grow underground, the gleba stays fleshy, and the spores are spread by animals (wild boar, for example) that eat the mushrooms, drawn by their strong smell.

- In stinkhorns (Phallus), the inner spore mass turns into a foul-smelling greenish slime, which is carried outward on a special receptacle and attracts flies — the main spore dispersers.

For a forager, identifying mushrooms with a chambered hymenophore always means cutting the fruiting body in half. The color and texture of the gleba are the key markers: a white, firm gleba often indicates an edible puffball, while a black, purple or powdery gleba means the mushroom is already old or belongs to an inedible/poisonous species (earthballs, for example).

Questions and answers

What is the gleba?
The gleba is the inner fleshy or spore-bearing mass of mushrooms with a chambered hymenophore (gasteromycetes). It consists of chambers lined with hymenium and contains spores that mature inside the mushroom.
How do puffballs release their spores if the hymenophore is enclosed?
When the spores in the gleba mature, the inner tissue turns to dust. At this point the mushroom's outer skin (the peridium) thins out and an opening forms at the top, or it simply splits. Any mechanical pressure (a raindrop, an animal's step) works like a bellows, blowing a cloud of spores out.
Are all mushrooms with a chambered hymenophore safe?
No. Although all true puffballs (Lycoperdon, Calvatia) with a perfectly white gleba are edible, there are poisonous mushrooms with a similar structure — for example, earthballs (Scleroderma), whose gleba is dark, purplish-black and tough right from the start.
Why is it important to cut a "ball" mushroom in half?
Only a cross-section lets you tell an edible puffball (pure white, uniform gleba) from a poisonous earthball (dark gleba) or from a dangerous death cap at the "egg" stage (the cut will show the outline of the future cap and stem instead of a uniform mass).

Sources

  1. 1.Зерова М.Я. та ін. Визначник грибів України. 1979
  2. 2.Roger Phillips. Mushrooms (Roger Phillips)
  3. 3.David Arora. Mushrooms Demystified
  4. 4.Index Fungorum