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General_Interest
Dandy



Registered: 05/11/20
Posts: 24
Loc: Montreal
Last seen: 3 years, 1 month
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Why do spore bearing surfaces face downwards?
#27023636 - 11/05/20 04:56 PM (3 years, 2 months ago) |
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Hi, yesterday I was in the woods looking for mushies, and found a birch fully parasitized by Fomitopsis betulina. There were fruits as high as 10 feet off of the ground.
It occurred to me that mushrooms that can disperse spores from as tall a distance above the ground as possible must have an evolutionary advantage in spreading their genetic material. To me, it seems obvious that the spore dispersal from a higher altitude would cover significantly more distance.
So my question is, if mushrooms are capable of creating their own air currents to propel the spores out of the fruit, why wouldn't the spore bearing surfaces be on top of the cap instead of the bottom? wouldn't it allow for a slightly more advantageous spore dispersal?
I'm not so selfish as to think that I am smarter than millions of years of evolution. Obviously there must be advantages to a covered hymenium. I'm just curious what they are.
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Dr. Funtime
Wipes Sideways

Registered: 02/04/13
Posts: 134
Last seen: 6 days, 59 minutes
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Re: Why do spore bearing surfaces face downwards? [Re: General_Interest]
#27023725 - 11/05/20 05:46 PM (3 years, 2 months ago) |
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I would assume to protect them from water. An inverted mushroom cap would act like a basin. Also If the cap faced up the spores would need some sort of ejection mechanism to get out, as opposed to just falling out with gravity.
Just some guesses.
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The Thing
ТнغТнརиو


Registered: 03/01/18
Posts: 1,539
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Re: Why do spore bearing surfaces face downwards? [Re: Dr. Funtime]
#27023747 - 11/05/20 06:04 PM (3 years, 2 months ago) |
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I think its to protect the majority from rain.
I always try to place a few mushrooms in tree branches at about eye level when i go foraging, just to help the spores disperse a bit further in the wind as compensation for the ones i've picked.
Got to keep the balance out there.
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Sandstone
Cosmonaut

Registered: 09/23/20
Posts: 88
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Re: Why do spore bearing surfaces face downwards? [Re: The Thing]
#27024218 - 11/06/20 12:07 AM (3 years, 2 months ago) |
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Quote:
The Thing said: I think its to protect the majority from rain.
I always try to place a few mushrooms in tree branches at about eye level when i go foraging, just to help the spores disperse a bit further in the wind as compensation for the ones i've picked.
Got to keep the balance out there.
That's neat trick, thanks.
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The Thing
ТнغТнརиو


Registered: 03/01/18
Posts: 1,539
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Re: Why do spore bearing surfaces face downwards? [Re: Sandstone]
#27025238 - 11/06/20 03:15 PM (3 years, 2 months ago) |
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Smartattack
C'mon man



Registered: 12/21/18
Posts: 3,775
Loc: A thought
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Re: Why do spore bearing surfaces face downwards? [Re: The Thing]
#27027728 - 11/07/20 11:04 PM (3 years, 2 months ago) |
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They actually do. Look at a fully mature cube. the gills end up on top in due time.
-------------------- * Smarts videos * Planet of the APES   I'm a fungal white supremacist.
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Alan Rockefeller
Mycologist

Registered: 03/10/07
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Re: Why do spore bearing surfaces face downwards? [Re: Smartattack]
#27027850 - 11/08/20 01:22 AM (3 years, 2 months ago) |
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If the hymenophore is on top, the spore will fall right back down on the mushroom and go nowhere. With the spores being produced on the bottom, they can fall and catch an air current.
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Solipsis
m̶a̶d̶ disappointed scientist


Registered: 12/28/09
Posts: 3,398
Loc: the Neitherlands
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Re: Why do spore bearing surfaces face downwards? [Re: Alan Rockefeller]
#27034344 - 11/11/20 11:24 PM (3 years, 2 months ago) |
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I think many mushrooms produce convection which can have the spores land on top of the cap. At a bit of an angle not sure if ballistospory could get em out into the world just fine, I wonder. What about resupinate fungi?
Mushroom caps upside down tend to be exposed to sun's UV which could cause more mutations than healthy. At least I wanna assume this is why if you put shiitake caps upside down in sunlight they make extra high levels of vitamin D which afaik is like for us associated with tanning and UV protection. Anyway maybe there are multiple reasons, some making more sure than others that this is not selected for unless under well regulated circumstances? With the factors mentioned so far seems like a nice list of pros for letting gravity do much more of the work, shielding from sun, but this is with agarics...
What about cup fungi though? or bird's nest fungi? There are always exceptions to the rules, if some of these problems are tackled or a non-issue under specific circumstances.
Tho i gotta say bird's nest fungi really overthought it, with incredible design in the end...
Getting back to the OP: yes it is a possibility, filled in a specific niche: Pilobolus shooting away spores with force from off of dung, calibrating to make sure they aim back into the meadow (and not into the woods off of the meadow) for the complicated spore packages to get eaten by horses and complete the cycle I think.
But for the average mushroom it seems more effective than enough to not invest like that in shooting some away far but rather setting up more or less robustly to a bit more passively indeed just use the wind air currents to spread so much more massive numbers of spores.
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