#193: Stropharia rugosoannulata, The Wine Cap

Many mushrooms like growing in mulch, but none enjoy that life more than Stropharia rugosoannulata. Commonly known as “the Wine Cap” or “the King Stropharia,” S. rugosoannulata is easily recognized by its habitat and wine-red cap – at least when young. The mushrooms quickly lose their color, so identifying older mushrooms hinges on other features, like the cogwheeled ring and dark purplish spore print. This mushroom is considered edible; mushroom hunters often collect and eat the Wine Cap and some even cultivate it.^1–4

Description

S. rugosoannulata is a medium to large umbrella-shaped agaric. Like most of its relatives, it has a circular pileus and a central stipe. The mushrooms grow 8-20cm tall and 4-15cm wide, but can get much bigger; the larger specimens can weigh three pounds or more! Other than that, S. rugosoannulata is typical of its genus.^1–4

The most distinctive feature of the Wine Cap is its pileus, which is a deep shade of red reminiscent of red wine. Other than that distinctive color, the cap is boring; it is smooth, starts out convex, and ends almost flat. Unfortunately, the cap’s wine-red color fades as the mushroom ages. By the time it is fully grown, the cap is light brown to whitish. Sometimes, partial veil material sticks to the edge of the pileus. This material is thin and not very noticeable until it gets colored by the mushroom’s dark spores.^1–4

Underneath the pileus, S. rugosoannulata produces attached gills that start grayish but become blackish purple as the spores mature.^1–4 The gills deposit a purple-black spore print. These features are standard for Stropharia species and can help you identify the mushroom’s genus.

The stipe is also uninteresting. It is straight and whitish but yellows with age. The bottom of the stipe attaches to white cords of mycelium that extend into the substrate. Sometimes, the base of the stipe enlarges to form a small bulb-like feature. The most useful feature of the stipe is the ring. Located about halfway up the stipe or higher, the ring is thick and white. The upper surface of the ring is covered in gill-like radial ridges; these are easiest to see when the dark spores are released and begin collecting on the ring. On the bottom of the ring there are raised rectangular areas of tissue arranged in a cogwheel pattern. Unfortunately, the ring is not very well attached to the stipe and easily falls off. As a result, you can’t rely only on the ring for proper identification of S. rugosoannulata.^1–4

Inside the mushroom, the Wine Cap produces firm white tissue that has no distinctive scent or flavor. The flesh does not change color when injured and is therefore not very useful for identification purposes.^1–4

Ecology

The Wine Cap is primarily found in mulch beds, gardens, and similar artificial habitats.^1–4 Where it appears in the wild, you usually find it where mulch has washed down and collected with sticks and other plant debris.¹ These areas, often along stream beds, are nature’s equivalent of mulch piles. In central Europe, there are areas where the fungus has adapted enough to the environment that it is regularly found growing in the wild. S. rugosoannulata has a worldwide distribution, thanks to plant imports. It is now possible to find the Wine Cap almost everywhere that mulch and similar plant products are used. Because of this human-mediated distribution, mycologists do not know where the fungus came from originally.³ It was first described from America in 1922,⁴ but it seems likely that S. rugosoannulata already had a global distribution at that point. Wine Caps appear any time the conditions are right from spring through fall.^1,2,4

Similar Species

A very large umbrella-shaped brown mushroom growing in mulch? It’s probably S. rogosoannulata. Small mushrooms growing in mulch with dark red caps? They’re most likely Wine Caps. A medium-sized brownish mushroom growing in mulch… that’s a bit trickier; there are many mushrooms which fit that description. If you find a mushroom like that, take a spore print to help narrow down your options. Agrocybe spp., for example, produce a medium brown spore print,⁵ which helps distinguish them. Even if you get a dark brown spore print, you will still have to use a field guide to separate out all the similar stropharioid mushrooms.

Edibility and Uses

The Wine Cap is considered edible, and some even say it is choice.^2,4 This is good news for mushroom hunters, since S. rugosoannulata frequently fruits in abundance and you often find more mushrooms than you can eat. On top of that, some people are probably happy that you want to get rid of the mushrooms in their garden.

Because the King Stropharia likes growing in artificial habitats such as mulch piles, it is a very easy mushroom to cultivate.⁶ Numerous companies sell Wine Cap spawn, but it is easy to cultivate on your own as well (see this site for detailed cultivation instructions).

S. rugosoannulata is also used for its ability to release nutrients into the soil. In Europe, it was widely used to help break down mulch and thereby support the growth of corn crops.³ So, even if you don’t like the mushrooms in your garden, they are actually beneficial to your plants!

Taxonomy

Although the King Stropharia’s name is officially S. rugosoannulata, various authors spell it S. rugoso-annulata or S. rugoso annulata. The mushroom also has many common names, which is not surprising given the Wine Cap’s widespread distribution. In addition to variants on “Wine Cap,” S. rugosoannulata sometimes bears the names “Burgundy Mushroom,” “Garden Giant,” and “Wine Roundhead” (British).^2–4,7

Kingdom	Fungi
Division (Phylum)	Basidiomycota
Subdivision (Subphylum)	Agaricomycotina
Class	Agaricomycetes
Subclass	Agaricomycetidae
Order	Agaricales
Family	Strophariaceae
Genus	Stropharia
Species	Stropharia rugosoannulata Farl. ex Murrill8