Armillaria ectypa

What You Should Know

Armillaria ectypa is a species of mushroom in the family Physalacriaceae. It prefers growing in sphagnum bogs with mosses. It is classified as endangered in Great Britain, and is protected under the Wildlife and Countryside Act 1981; it is also on the provisional European red data list.

This mushroom belongs to the Desarmillaria subgenus which is characterized by exannulate stipes. It is probably the only Armillaria species that is not linked to the degradation of wood, rather is saprotrophic on decaying peat moss and other bryophytes. The habitat preferences are majorly confined to niches with low nitrogen availability and alkaline microhabitats. A. ectypa can be found typically in alkaline mires, ombrogenous peat bogs, and reeds where the species diversity ranges from mosses to flowering plant species, suggesting that A. ectypa also plays a role in nutrient cycling in wetlands.

Other names: Marsh Honey Fungus.

Armillaria ectypa Mushroom Identification

1. Cap

   The cap of the fruiting body can be up to 10cm wide and the stem 10 cm tall at its maximum. The cap is convex to fairly flat, sometimes with a depressed center with age and it has a yellowish-brown to brown color. The center of the cap can be scaly and the edge of the cap can be striate with the gills visible through the cap. It is hygrophanous, coming much paler in color when drying and quite thin with little flesh.

2. Gills

   The gills are cream to pinkish and can curve downwards where they join the stem, although often they join the stem at 90°.

3. Stem

   The stem is pale brownish and unlike the common honey fungus, has neither a ring nor rhizomorphs or ‘bootlaces’ attached to the base of the stem.

4. Habitat

   It can grow in dense clumps or singly.

5. Spore Print

   White.

6. Similar Species

   Other species of Armillaria are noted by usually having a ring, distinct rhizomorphs or “bootlaces” extending from the base of the stem and a different habitat (usually in woods, gardens or on dead wood). In a fen or on a bog, fruiting body size, form (e.g. flat to convex cap often growing in clumps) and the white spore print rule out most other species except Tephrocybe (Lyophyllum) palustris which is smaller with a narrower stem and various species of Clitocybe which have to be carefully checked for microscopically.

Sources:

Photo 1 - Author: Pärismaalane (Creative Commons Attribution-Share Alike 4.0 International)

Photo 2 - Author: Lukas from London, England (Creative Commons Attribution-Share Alike 2.0 Generic)