Minnesota Fungi

Phyllosticta minima is a common and widespread fungus. It occurs in eastern North America and west to the Great Plains. It causes a disease known as Purple Bordered Leaf Spot on maples. It infects mostly Amur, Japanese, red, and silver maple, but also mountain and sugar maple, and in other areas, Tartarian and sycamore maple.

The infected leaf develops small, round, tan spots with purple or brown margins. Tiny, black, pimple-like fruiting bodies form in each spot. The dead tissue in the middle of the spot sometimes breaks away, leaving a small hole.

Infections are most common in wet years and on the bottom third of the tree. Some infected leaves may eventually turn brown and drop off the tree, but most trees are able to withstand the infection. Control involves removing leaves with spots from the tree, and raking up and removing fallen leaves. That prevents further infections in the current growing season, and reduces the number of infected leaves that will overwinter.

Gilled Polypore (Lenzites betulina) looks very much like a Turkey Tail but the pore surface on the underside has gills. It is widespread across Europe, Asia, and North and South America. In the United States it is very common from the East Coast to the Great Lakes states, south to Texas, and on the West Coast. It is less common in Minnesota where it is at the western edge of its range. It is found usually in overlapping rows or columns on logs and stumps of a wide variety of hardwoods, especially oak and willow.

The name Gilled Polypore sounds like an oxymoron but accurately describes this mushroom. The fruiting body is a small, fan-shaped to nearly round, shelf-like bracket. The upper surface is concentrically zoned with varying textures and and colors, and is densely hairy. The gills are white when young but darken as they age. The flesh is thin, tough, and inedible.

Chicken Fat Mushroom (Suillus americanus) is a widespread and very common “Slippery Jack” mushroom. It occurs in North America east of the Rocky Mountains. It is very common in the United States from the northeast to the Midwest, and in adjacent Canadian provinces. It is common Minnesota in the northeast, north-central, and metro regions. It grows on the ground, usually in groups but not clustered, exclusively under eastern white pine. It is found from mid-July to mid-September in mixed and coniferous forests and anywhere else its host is found.

When young, the cap is bright yellow, convex, and slimy. As it matures, the cap becomes broadly convex and sometimes has a small bump in the middle. The mature cap is sticky or slimy when moist, and frequently has reddish-brown scales, streaks, and/or patches, especially near the margin. The underside of the cap is a sponge-like pore surface.

Chicken Fat Mushroom is edible but the taste is not distinctive, and the cap becomes slimy when moistened. After removing the slimy skin and the spongy pore surface, there is little left to enjoy.

King Alfred’s Cakes (Daldinia concentrica) is a common fungus that occurs on all continents except Greenland and Antarctica. It grows on dead or dying deciduous wood, especially ash. The fruiting body is ball-shaped, stalkless, and hard. It is brown when young, black and shiny when mature. The surface is densely covered with minute, pimply bumps. These bumps are tiny, spore-bearing chambers just under the surface. When the spores are mature they burst open during the night and eject up to an inch or more large numbers of black spores. These spores are often visible on the bark near the fungus long after they have worn off the fruiting body.

The common name King Alfred’s Cakes refers to a story told about a British monarch. King Alfred fled from a battle and took refuge in a peasant woman’s house. The woman asked him to watch her cakes in the oven. Preoccupied with his own troubles, he let the cakes burn. This earned him a scolding from the woman who did not know her visitor was the king.

King Alfred’s Cakes is also called Coal Fungus, but not just for its appearance. An older, black specimen, when broken to expose the interior, will readily take a spark from a fire steel. Blow on the glowing spark and it will grow in size. Left alone, it will smolder for a long time. Placed against dry tinder and blown upon, it will ignite a fire. Another common name, “Cramp Balls”, refers to the belief that when carried in a pocket it can prevent or cure leg cramps.

Common Bird’s Nest (Crucibulum laeve) is called that because it looks like a bird’s nest with several eggs. It occurs on all continents except Greenland and Antarctica. It may be the most common bird’s nest fungus in Canada and the northern two-thirds of the United States. It grows on sticks, wood chips, humus, vegetable debris, and manure. Although common, its small size makes it difficult to see.

The fruiting body is a very small bowl-shaped “nest” containing several tiny, egg-like capsules. When young, it is yellowish, densely hairy, and topped with a yellowish lid. Eventually, the outer surface sloughs off and the lid ruptures and disappears. The mature mushroom has a hairless, brown, shiny, outer surface, and a smooth, white inner surface. Inside the hollow nest are several tiny, white, circular, flattened capsules (eggs). The eggs are attached to the side of the nest by a long, thin, elastic, white cord that can be seen only with a hand lens, a needle, and a lot of patience. The eggs are disbursed by raindrops and wind. Common Bird’s Nest may be edible but is too small and tough to be worth the effort.

Choke Disease of Grasses (Epichloe typhina)

Rust of Prickly Ash (Puccinia andropogonis var. xanthoxyli)

Oak Leaf Blister (Taphrina caerulescens)

Flowery Blewit (Lepista irina)

Trembling Phlebia (Phlebia tremellosa)

Handsome Club (Clavulinopsis laeticolor)