Tagged: ecology

how fungi relate to other living things

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#011: Characteristics of Fungi

What is a fungus?  That question has been answered many ways over the years, reflecting an evolving understanding of this strange group of organisms.  Initially, fungi were classified as a class in kingdom Plantae.  As our understanding of the chemistry, life history, and evolution of fungi improved, Fungi was elevated to the rank of kingdom.  Kingdom Fungi is placed in domain Eukarya and belongs to the major clade Opisthokonta.  Opisthokonta also includes the kingdom Animalia, which makes animals close relatives of the fungi.  But going beyond taxonomic definitions, what makes a fungus a fungus?  It’s hard to answer that question because the fungal kingdom is very diverse and there are many similar organisms in other kingdoms.  As a simple answer, Fungi are heterotrophic filamentous (or unicellular) eukaryotes with a chitin cell wall that reproduce by spores and digest their food externally.

Buglossoporus quercinus 4

#229: Buglossoporus quercinus

Buglossoporus quercinus is an interesting polypore that most of you probably haven’t seen before.  I’ve seen it only once, myself, brought in at a mushroom club meeting.  It reminds me of a yellow version of Ischnoderma resinosum.  B. quercinus forms brackets that are fuzzy yellow on top with a white pore surface below.  All parts of the mushroom stain brown when handled.  The coloration and staining make it a unique mushroom.  The Global Fungal Red List Initiative lists B. quercinus as “vulnerable” because it is rarely found and grows on only old oak trees – a habitat that is in decline across Europe.  Although B. quercinus is primarily known from Europe, it was recently discovered growing in eastern North America.

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#228: Dutch Elm Disease

Elm trees were once the defining tree of American life, widely planted in cities, suburbs, and farms.  This changed beginning in the early 1900’s when Dutch Elm Disease arrived on the continent.  Caused by the fungi Ophiostoma ulmi and O. novo-ulmi, Dutch Elm Disease blocks off the water transportation tissues in elm trees, leading to wilting and death.  The fungus moves between trees by using elm bark beetles as vectors and by growing from tree to tree, making it a difficult pathogen to control.  The best way to manage Dutch Elm Disease today is by planting resistant cultivars – fortunately, there are many resistant options available.

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2018 Fall and Winter Fungal News Update

Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of news stories that have taught me something about fungi from September through December 2018. Read each summary to learn about: zombie ants, mushroom poisonings, White Nose Syndrome, Bananas, and more.

cryphonectria parasitica on wood 1

#222: Cryphonectria parasitica, Chestnut Blight

The American Chestnut Tree, Castanea dentata, was once one of the dominant trees in eastern North American forests. It rivalled oak trees in terms of size and abundance. The trees were also highly valued for their rot-resistant wood and edible seeds, making it one of the most economically important trees in eastern North America. So, if the trees were so common and so important, where are they today? The downfall of the American Chestnut began in New York in 1904, when a disease called Chestnut Blight suddenly appeared and swept across the continent. By 1950, the disease had infected and killed almost every American Chestnut. Chestnut Blight is caused by the Asian fungus Cryphonectria parasitica, which grows in the outer wood of the tree and essentially chokes trees to death. The aggressive pathogen has doomed the American Chestnut to extinction, unless humans can come up with a solution.

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Spring 2018 Fungal News Update

Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of news stories that have taught me something about fungi from mid-February through mid-May 2018. Read each summary to learn about: gut fungi, ambrosia beetles, gravity detection, prehistoric mushroom use, diseases of toes, ants, frogs, bats, and ohia trees, and more.

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#087: Gymnosporangium juniperi-virginianae, Cedar-Apple Rust

Gymnosporangium juniperi-virginianae is a rust fungus known as Cedar-Apple Rust (sometimes abbreviated to CAR) that causes disease in Eastern Red Cedar and in apple trees. This fungus is unique among rusts because it produces large fruiting bodies. On cedar trees, the fruiting bodies resemble lumpy brown golf balls with long gelatinous orange tentacles bursting out of them. On apple trees, the disease causes more damage but produces only orangish spots. The complex life cycle of Cedar-Apple Rust means the fungus is easy to control, although these control methods resulted in a legal case that was argued before the Supreme Court of the United States!

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2017 Mycorrhizal Mushroom Map:
1 Year, 1 Yard, 499 Mushrooms

In October of 2016, I stepped out into my back yard and found it carpeted with medium-sized brown mushrooms. Apparently, I had nothing better to do that day than attempt to identify these boring nondescript mushrooms, so I sat down with a field guide and managed to key them out to Inocybe rimosa. This was a surprising result; most of the boring brown mushrooms that pop up in yards are saprobic, but Inocybe is a mycorrhizal genus. Since I. rimosa is mycorrhizal, there is only a very limited area in my yard that it can grow. This made me wonder, “Will it grow in the same place next year?” There was only one way to answer that question: keep track of where mushrooms appear in my yard. I logged all 227 I. rimosa mushrooms and waited eagerly for 2017, when I would map all the mycorrhizal mushrooms that appeared.

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#021: Pleurotus ostreatus, The Oyster Mushroom

Pleurotus ostreatus, the “Oyster Mushroom,” is the quintessential pleurotoid mushroom: it is a gilled mushroom with a very short stalk that fruits from the sides of logs. Oyster Mushrooms are some of the best edible wild mushrooms; they are fairly easy to identify, they are meaty, and they appear in large numbers. Additionally, you find them in late fall and winter, when the woods are otherwise boring places for mushroom hunters. Although it grows on hardwood logs in nature, P. ostreatus will decompose pretty much any plant material, which makes it very easy to cultivate. As an added bonus, the Oyster Mushroom attacks nematodes. That’s one cool mushroom, right?

Wheat Leaf Rust, Wheat Stripe Rust, and Wheat Stem Rust 1

#208: Rust Diseases of Wheat

Wheat is the most widely grown crop in the world and is a staple food for billions of people. Diseases affecting wheat are therefore of utmost importance to food security. Some of the most destructive and difficult wheat diseases are the rusts. Wheat rust comes in three varieties: Leaf Rust, Stem Rust, and Stripe Rust, each caused by a different species of fungus. These all look slightly different but all cause rust-colored blemishes on wheat surfaces. The three species are closely related and have nearly identical life cycles. Despite this, managing the diseases is complicated and requires using resistant wheat strains, proper cultural practices, and fungicides.