Posted by: Rob Viens | February 10, 2013

Darwin’s Fungus

Darwin did not have much to write about on the 10th, merely stating:

“Removed to a bay North of Orange Bay.” (Feb 10)

So I’ll use the opportunity to continue the story of the southern forests. Today – the story of a little yellow golf-ball shaped fungus that Darwin found growing on the trees. As it bears his name, it only seems fair that he should have the first chance to describe it:

“In the Beech forests, the trees are much diseased: on the rough excrescences vast numbers of yellow balls grow.— These are of the colour of yolk of an egg.— & vary in size from a bullet to a small apple.— in shape globular, but a little produced towards the footstalk or point of attachment. They grow both on the branches & stems in groups…

Sketch of Darwin’s fungus from Voyage of the Beagle:

Cyttaria darwinii

The external surface was marked with white spaces, as of a membrane covering a cell. Upon keeping one in a drawer my attention was called after some interval by finding it become nearly dry.— the whole surface honeycombed by regular cells & possessed of the decided smell of a Fungus.” (Zoological Notebook)

Although sailors where aware of this particular fungus, Darwin was the first to offer a scientific description. So when his samples were returned to England and officially described by the mycologist Rev. Miles Berkeley. The Reverend chose to name the fungus after the young naturalist – calling it Cyttaria darwinii.

Cyttaria darwinii (from Arthur Chapman)

 

 

Keep in mind that a fungus is not a plant – it belongs to one of the 6 main Kingdoms of Life. (For the sake of argument I’ll go with six, but I know some biologists divide the Kingdoms up a little differently.) The three metazoan Kingdoms include the animals, plants and fungi (the rest are basically single-celled organisms). Hence, although they might look like plants on the surface, fungi are not plants – they are an entirely separate group of life.

 

Now here it the really cool part – not only are fungi not plants, but on the evolutionary “tree of life” they are actually more closely related to animals.  They have to digest food just like we do and then absorb the nutrients.  Of course, they digest their food externally – excreting enzymes to break down tissue before they can absorb the nutrients. That is what makes them such good decomposers/detrivores. Think about it – mushrooms are more like you then they are like a tree!

The other thing to know about fungi is that the part of the organism we often see – the “mushrooms”, or in this case the spongy, yellow “golf balls” growing on the beech tree – are really just the fruiting body of the fungus.  Most of the fungi is living out of sight – underground or in the tree.

Cyttaria darwinii only grow on the Southern beech tree, so their fate and that of the tree are one in the same.  Hence, Cyttaria are only found in the southern hemisphere, and this particular species is only found in South America. The fungus releases a chemical that causes the tree to produce a gall (a big gnarly lump) that supports its growth.  Every spring and summer the orange fruiting bodies then grow out of the gall.  And in this case, “fruit” is the right word, as the native people harvested and ate them as a significant part of their diet.

As a charter member of the Gluttony Club back in his college days, Darwin rarely passed up the opportunity to try something new to eat.  The fungus was no exception:

“When young.— they contain much fluid & are tasteless, but in their older & altered state they form a very essential article of food for the Fuegians.— The boys collect them, & they are eaten raw uncooked with the fish.” (Zoological Notebook)

And in case you were wondering…

“It has a mucilaginous, slightly sweet taste, with a faint smell like that of a mushroom.” (Voyage of the Beagle)

Aside from being mucilaginous (mmmm, yum), Darwin also described an additional source of protein that he found in the fungi:

“It is however especially to be noted I cut open great numbers & scarcely ever found the central cellular part without one or more larvæ of the same sort.— In the young state I unfortunately neglected to examine them.— Now I am in doubt whether it is an excrescence formed for the nourishment of some insect or a true cryptogamic plant” (Zoological Notebook)

Amazingly here are Darwin’s actual samples of Cyttaria darwinii, preserved at the Kew Royal Botanical Garden (the photo is from Kew)

Darwin's Fungus

Lastly, in the spirit of My Botanical Garden, here is the taxonomy of Darwin’s Fungus:

Kingdom: Fungi

Phylum: Ascomycota

Subphylum: Pezizomycotina

Class: Leotiomycetes

Order: Cyttariales

Family: Cyttariaceae

Genus: Cyttaria

Species: C. darwinii

 

PS – In the world of strange coincidences, check out the recent post on these fungi that appeared in a Scientific American Blog called Darwin’s Neon Golf Balls.

(RJV)

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Responses

  1. Reblogged this on My Botanical Garden and commented:
    Welcome on board, My Botanical Garden readers, we are still on journey with Rob Viens and Darwin! This time Beagle sails around the Cyttaria darwinii! Rob thank you for this fantastic post!

  2. Rob thank you again for your contribution-your posts are always teaching something new ! It is such a great opportunity for My Botanical Garden to sail new horizons with Beagle and its crew!

    • Thanks Tamara – the pleasure is all mine. It is fun to cross-pollenate blogs and it was great to have some of your readers check out the Beagle Project. I posted the third installment today (on sphagnum) – thanks again for the opportunity. Let me know when you are ready for me to post your guest blog on Wedgwood Pottery! – Rob

      • Hi, Rob! thank you again for your contributions-I see my Botanical garden readers really like your posts! Have to hurry up with my post for The Beagle project 😉
        Tamara

  3. Reblogged this on Old School Garden.

  4. What amazingly beautiful creatures!

  5. […] ist uns aufgefallen. Er lebt als Halb-Schmarotzer auf Bäumen und trägt kleine orangefarbene Kügelchen als Früchte. Sie sind essbar und werden für Marmelade […]


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