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Green Stain Fungus Fruiting

10-15-15 blue green cup fungus 038Sac fungi, or ascomycetes, are a division of fungi, most of which possess sacs, or asci, in which spores are produced. The relatively common blue-green cup fungi, Chlorociboria aeruginascens and its close relative, Chlorociboria aeruginosa, are in this group and are referred to as Green Stain Fungi. (They differ microscopically by the size of their spores.) Most of the time you do not see the actual fruiting bodies of these fungi (see photo). More often you come across the brilliantly blue-green stained wood (these fungi grow on the rotting logs or barkless wood of poplar, aspen, ash and especially oak) for which these fungi are responsible. Woodworkers call this wood “green rot” or “green stain.” 14th and 15th century Italian Renaissance woodworkers used Chlorociboria-infected wood to provide the green colors in their intricate wood inlays. The blue-green discoloration is caused by the production of the pigment xylindein, which can inhibit plant germination and has been tested as an algaecide. Xylindein may make wood less appealing to termites, and has been studied for its cancer-fighting properties.

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11 responses

  1. Marilyn

    This seems to explain the bits of green wood found on the forest floor. Green all the way through, as I recall.

    October 15, 2015 at 8:28 am

  2. Jane Swift

    Mary, do those blue-green stained pieces of wood fluoresce?

    October 15, 2015 at 8:46 am

    • I believe not, but there are close to 80 species of fungi that do!

      October 15, 2015 at 9:02 am

  3. Alice Pratt

    Our awesome world is so incredibly interesting and diverse, let’s take really good care of it! 😍

    October 15, 2015 at 9:16 am

  4. Mary, I have just concluded that if I’m patient, I will find the answers to anything I have wondered about, during my wanderings in the natural world (and a whole lot of other things I haven’t even known to wonder about), by reading your offerings each day! That blue-green coloration of rotting wood has always fascinated me, but I never researched for an explanation.
    In fact, it’s so much more pleasing to learn about all these wonders in your blog – because of the careful choices you make re. interesting facts to include, AND your remarkable photos – than it is through a Google search. ¡Mil gracias! – Dell

    October 15, 2015 at 10:10 am

    • Oh, Dell. I have a feeling you know MORE than I do. Thank you for your kind words!

      October 15, 2015 at 11:13 am

  5. Lucky you, I haven’t encountered these fruiting bodies in about five years, though lots of stained wood. This color is so striking to find in terrestrial New England. Great choice to highlight!

    October 15, 2015 at 10:23 am

  6. I’ve seen the blue-green wood, but never the fruiting bodies. How cool it would be to come across some!

    October 15, 2015 at 6:56 pm

  7. Wow! I didn’t know all of those details about this particularly fascinating fungi. I have a couple of small pieces of wood from last year that were totally stained blue-green which I intend to turn into earrings soon!

    October 16, 2015 at 6:31 am

    • I bet your earrings will be beautiful! What a great idea – glad the wood isn’t too punky!

      October 16, 2015 at 8:00 am

  8. This is a new one for me! How interesting. I’ve haven’t seen them anything like that in my walks here.

    October 16, 2015 at 8:25 am

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