Speciation by conglomeration - a further notion.

Perhaps you have heard of the largest single flower in the world?
Let us be clear.
It is a single flower.
It is not a composite of flowers (the largest of these of which is produced by the famous Amorphophallus titanum ).

No, the largest single flower in the world,
up to about 20-inches (50 cm) across,
is produced by Rafflesia arnoldii.

And yet to see the plant that produces this enormous flower
you will need a microscope.
Yes, this is true!
For Rafflesia arnoldii is present only as a network of filaments in the plant of which it parasitizes,
a large vine in the tropics of Sumatra. [I implore you to come back to this story after departing, momentarily I hope, to view this rather stunning observation of Rafflesia arnodlii : https://www.inaturalist.org/observations/2696444 ]

Oh good, you made it back.

Now the rather spectacularly example of plant parasitic on another plant
also occurs at much smaller dimensions,
with fungi that parasitize other fungi,
of which we will then take one step further.

A lichen is a combination of a fungus and an algae that act as one.
Lichens are thus excellent examples of species that are each a conglomeration.
Ramalina americana is one such lichen.
It looks like a minuscule, green, flat-stemmed shrub
that grows on the branches of trees,
and does so throughout much of North America.

The spore-bearing reproductive structures,
the "flowers" as it were,
of Ramalinae americana
are the button-like discs seen in this photo: https://www.inaturalist.org/observations/192660601
[These "flowers" are in lichenological parlance, apothecia.]
Please note how the buttons have a flat top.
This is their normal form.

Tremella ramalinae is a fungus that parasitizes the lichen Ramalina americana.
Just as with Rafflesia,
nothing is seen of Tremella
until its "flowers" erupt through the tissue of its host species.

The spore-bearing "flowers" of parasitic Tremella species
are brain-like in appearance.
This makes them rather distinct and easy to separate from the normal growth of whatever host they happen to parasitize,
as on this example of Tremella parmeliarum on its host, Parmotrema reticulatum :

And that is how it is supposed to be with Tremella ramalinae on its host Ramalina americana.
However, Tremella ramalinae has taken things one step further.
Instead of erupting its spore-bearing structures through the body of its host,
and separate from its host's own spore-bearing structures,
there are examples where some Tremella ramalinae have united the spore-bearing structure with that of the host,
so that the two act as one. https://www.inaturalist.org/observations/191782364

It appears that the parasite and the host have become one.

[There are at least 4 other observations of this specific occurrence on iNaturalist.]

Posted on November 30, 2023 01:27 PM by mjpapay mjpapay