Where did land plants come from?


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If someone says land plants came from Mars, too, I am gonna barf. Does EVERYTHING have to come from freakin’ Mars?


It’s OK, no need to thank me all at once.


Of course they didn’t come from Mars, that would be ridiculous. They came from Venus.

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AAAAAAurggh!!! (bites nearest hand)

Not sure if I’m lichen this theory.


That joke is in really spoor taste.


Just mossing around.

Aw, come on, snig’s just a fungi.

Yeah, come on, we’re all bros, we shouldn’t be bryo phyting.

Sometimes we just can’t kelp it.

Please don’t misunderstand – I have no doubt that snig is a real fungi. What bothers me is all his buds.

Oh good grief. This story was old a decade ago among mycorrhizal researchers, and it’s been published many, many times. There are only two news items here: one is that it took you guys so long to notice this. The other is that they picked a mycoheterotroph (now there’s a story) to illustrate this when they should have picked some of the old pictures of mycorrhizal spores from the Rhynie chert (http://www.abdn.ac.uk/rhynie/fungi.htm) to show the original fossils which first tipped off researchers that mycorrhizae long pre-date roots. Actually, some of the oldest evidence for this relationship (indirectly) comes from a road cut in Wisconsin (http://www.ncbi.nlm.nih.gov/pubmed/10988069). The spores in question were spotted by an undergrad.

Now, if you want a story, look at the evolution of ectomycorrhizae. That symbiosis has evolved convergently at least a dozen separate times in the plant kingdom and at least five separate times convergently in the fungal kingdom. It’s the biggest example of convergent evolution known, and no one even studies it. Why not write on a real mystery?

The article cites a paper from 1975, so I don’t think anyone was claiming it was news. You’ve seen this xkcd cartoon?

It applies even more when it’s something “everyone knows” by the time they’re specialists on mycorrhizae. This was obviously for other people who might be interested in learning about them, hence the Indian pipes rather than spores indistinguishable to the non-mycologist; there’s no call to be a mycorrhizal research hipster about it.

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I agree with Heteromeles, this article was pretty terrible. My biggest beef is how it ends: land plants clearly did not arise as a ‘fusion’ of algal and fungal genomes, the speculative part of the 1993 article that forms the basis of the last two paragraphs of the ‘Wondrous stories’ post.

Land plants are basically land-adapted algae, closest relatives of the green algae still found in freshwater or marine habitats. There is no genomic evidence for them having ‘fused algal/fungal genomes’, though that’s not to say there may not be the odd gene hopping back and forth.

The 1993 article it refers to was written in the pre-genomic science era, and we now have lots of genomic data that contradicts the hypothesis (which was never taken seriously, as far as I know). Nor do land plants reflect new endosymbioic events (endosymbioses occur when one cell engulfs another, with the small internalized cells now ‘slaves,’ like mitochondria and choroplasts).

There are many fascinating mysteries about how plants invaded and diversified in terrestrial environments in partnerships with fungi. A truly bizarre one is the ‘indian pipe’ mentioned here (a plants that parasitizes fungi and their green plant partners) – but this is nothing to do with the fungal fusion hypothesis, though a non-specialist might think it supports that idea, as a strong distinction is not made in the text of the post.

So I find the xckd post and accusations of hipsterism off the mark here.

Those are good criticisms, that this is all old and everyone should have noticed it already is not. I can only speak for myself: I know enough about those things to know that phylogenetic trees mean any notable fungal ancestry was unlikely, and to know about some different groups of mycorrhizae and even how they differ. But I didn’t know they occurred even in ancient bryophytes, what this prompted me to find out. So somebody learned something, which is the point, right?

I agree that it’s great to find out, but your ignorance (forgive me) is a symptom of a bigger problem. Mycologists first got a clue back in the 1970s that land plants were enabled by fungi in the glomeromycota that need a photosynthesizing partner to live, and it came from the fossils in the Rhynie chert. They’ve even drawn some (very poorly known) cartoons about this. When I got involved with mycorrhizal research as a botanist in the 1990s, I spent a lot of time convincing other botanists that the field matters, and I still do. It gets frustrating that something so fundamentally weird, cool, and important is so systematically ignored that a crappy version of it gets transmitted as news on BoingBoing.

The problem is that US and England are mycophobic societies: to us, fungi are scary and icky, and unless we’re talking about yeast (bread and alcohol), we generally don’t want to deal with them at all. This attitude isn’t shared with other nations; much of Europe, Russia, and China have no problem eating fungi and working with them. For us, though, our cultural phobia has huge consequences beyond not eating mushrooms. We’re generally clueless about what mycorrhizal fungi can and can’t do: at best, most people treat spores as fairy dust to sprinkle on their gardens to make them grow better. Worse, there’s a huge, untapped potential role for using fungi for things like remediating industrial waste sites and cleaning up sewage, but a combination of a few badly written patents and (more generally) our societal phobia keeps us using the expensive, inefficient methods we generally have. For anyone who wants to know more, I strongly advise reading Stamets’ Mycelium Running. That’s a mind-blowing book too, and it has the virtue of being accurate.

And please, please, get over both the phobia and the ignorance. Fungi can be icky, but without them plants wouldn’t be here and neither would we.

Fungal phobia may be a problem, but it has nothing to do with why people don’t hear this stuff.

First, for non-biologists fungi are generally inaccessible. I know lots of the animals, plants, and even protozoans around where I live, but the mushrooms and lichens are a mystery to me. That’s not because I’m scared of them, it’s because recognizing them takes applying hypochlorite and making spore prints, and the classification has changed a great deal and no longer has much to do with even those kinds of features so you have to learn them on a case-by-case basis.

That right there is going to cut down on people who read more about mycorrhizae. But like I said, I have had occasion to look at some basic material and guides on them, and still never learned they predate roots. So that’s the second thing: this is evidently something only specialists discuss, not just among botanists, but even among mycologists writing about mycorrhizae.

So yes, I’m sorry to have been ignorant of this, but it’s not actually because of a culture that doesn’t eat so many mushrooms or for lack of interest in fungi. It’s because even looking into them it never got mentioned to me - only now thanks to this article it was, and now I know more about it. If you think it’s a shame we didn’t all already know, please don’t fault the ones who brought it up.

I’m afraid this tedious conversation has become Sphagnant.

@awjt, Sphagnum is a moss dude, get with the botanical program!

@Chenille, I’m really glad you’ve been excited by that post, but bad science is bad science, and worth calling, so please – don’t in turn find fault with those who call it.