I have an idea for a world:

Let's suppose that there is a tree that evolves a weird sort of flower: when the bud opens, instead of revealing the usual flowery bits, it reveals an animal-like entity that acts as it's gametophyte. This animal-like gametophyte (let's call it a faerie), after reaching maturity, leaves the parent tree and searches for a compatible mate. Once the mate is found, the two faeries sexually couple and fuse into a sporophyte sapling that eventually matures into a new "faerie tree", ready to produce new faeries.

My question is:

Would it be possible for faeries to develop sentience, or even humanoidism, and if so, how would it work?

And if they develop human level intelligence, how would the fact that sex results in the death of the faeries involved at the expense of the tree (which is basically non-sentient) affect faerie culture?

And going backwards a bit, how would animal-like gametophytes even evolve in the first place?

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    $\begingroup$ Welcome to WorldBuilding No Name! This is a great premise! But we have a "One question per post!" policy. Could you please edit your post to narrow it down to one question? Questions about societies are often difficult and it might be a good idea to start with what you already defined as the starting point: how would they evolve in the first place? You can later ask new questions incorporating the feedback from the older ones. If you have a moment please take the tour and visit the help center to learn more about the site. Looking forward to your contributions. Have fun! $\endgroup$
    – Secespitus
    Commented Sep 7, 2017 at 8:16
  • $\begingroup$ may I know what its life cycle would look like? I kept thinking of cordyceps as I imagine after mating both eventually die and a tree grows out of their carcasses and the cycle repeats, no seed is involved. $\endgroup$
    – user6760
    Commented Sep 7, 2017 at 8:41
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    $\begingroup$ For clarity, the question is based on how plant reproduction works. The male faerie (microgametophyte) is called a pollen grain; it leaves the anther which produced it and goes in search of a receptive stigma. The female faerie (megagametophyte) waits patiently for a microgametophyte to find it and provide the double fertilization to initiate embryogenesis. $\endgroup$
    – AlexP
    Commented Sep 7, 2017 at 10:10
  • $\begingroup$ The problem seems in getting nerves in plants see: $\endgroup$
    – user25818
    Commented Sep 7, 2017 at 22:40
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    $\begingroup$ Interesting question, but I think the scenario needs to be developed further. I cannot see a faerie society developing. Also I do not see the normal progress of a life cycle as 'death'. Metamorphosis is not 'death' and I doubt the faeries would necessarily see it that way. The main problem that you have though is faerie society: faeries are not born into families, they have no need of other faeries, except for sex to produce a faerie tree. The faerie tree, as effective parent, needs to have a more active role, I think - then you might get a society. $\endgroup$
    – Lee Leon
    Commented Sep 8, 2017 at 7:53

5 Answers 5


Such gametophyte constructs are unlikely, but possible.

It is highly probable, however, that such gametophite would have just what needed to perform their function: find a suitable partner, produce a fertilized seed and find a suitable place to burrow it.

Problem with "further development" is that, for this to work, a lot of things are not necessary, including any way to feed the fito-animal; it is highly likely the gametophyte would have a sugar reserve to last it "as long as necessary".

Schemes like "fused gametophytes become parasite to enlarge transport range" are very unlikely because a lot of functions would have to be "piggybacked" unto a perfectly working system without a clear evolutionary push.

OTOH developing even rudimentary "insect-like" gametophites implies some kind of "nervous system". If that is done it's highly unlikely Evolution would limit its usage to gametophites; the whole tree would start to act "more deliberately" (e.g.: growing branches in a well defined, environmentally conscious, direction), possibly leading to some form of conscience.

It would be far more likely to imagine some kind of symbiosis.

Note: any form of auto-conscience would need a rather large nervous system (of some kind, not necessarily based on neurons; most likely root apices-like formations would play an important role in plant "intelligence"), incompatible with (possibly large) insect-like creatures.


There are, in the real world, animals that have life-cycles rather similar to this.

Cnidarians, for example, have both polyp and medusa body forms, where the polyp is stationary and asexual, and the medusas are free-moving and sexual.

So, I'd go about this from the other direction: start with an animal, which develops a progressively more plant-like sessile stage.

That takes care of evolving animal-like gametophytes.

Would it be possible for faeries to develop sentience, or even humanoidism, and if so, how would it work?

And if they develop human level intelligence, how would the fact that sex results in the death of the faeries involved at the expense of the tree (which is basically non-sentient) affect faerie culture?

Do they know that the trees are non-sentient? Given the human propensity to believe in life after death, and the fact that these trees are in fact verifiably still living, I would imagine they would maintain a deep belief in the persistence of the parent fairies after they fuse.

If we presume that any individual plant-form can live for a comparatively long time compared to the mobile fairies, and produce a large number of fairies during its life, then we can also conclude that most fairies will not, in fact, become sessile and start reproducing themselves, rather like most tree seeds don't successfully germinate. If it were not so, they'd overpopulate rather quickly. Unlike regular plant seeds, however, "seeds" that are actually animals can be very useful to their parent and sibling trees. They can guard the trees, they can fertilize them, they can be around to care for newly-born fairies, etc. And that gives them a great excuse to develop societies and social intelligence.

Given only that level of detail, they wouldn't need to develop humanoid form, but I see no reason why they couldn't, either.


There's some good news and some bad news. The good news is that your general scenario is actually highly plausible. The bad news is that the call for sentience and humanoid form is less likely to occur evolutionary.

As for the plausibility of the mechanism, what you describe is basically what Jellyfish do for their reproductive cycle.

Jellyfish reproductive cycle

There's a minor difference in that the jellyfish are not actually the gametes, but rather are a "fairy" like creature that has the gametes. Their cycle is:

  • Start with a polyp, which is fixed to the ocean floor in a rather plant like manner.
  • When ready, the polyp buds, producing an ephyra, which grows into a full medusa. This is very much like your fairy.
  • The medusa mate. Each one is either male or female, and the males release sperm. The females hold onto the fertilized eggs until they mature, and they are then released as a planula.

That's really close to your system.

The harder question is sentience and humanoid form. Generally speaking, the humanoid form is unlikely to be an ideal form for a fairy sized creature. It's optimized for 3-7 foot tall creatures. Its highly likely that there is a related body layout which is better suited for small sizes, and whether that qualifies as "humanoid" is a harder question.

As for sentience, nobody knows what the requirements are for sentience, but it's generally assumed that there's a minimum level of processing power required. That involves brain volume, which is hard to come by when you're very very small.


For the reasons explained in other answers, having these intelligent gametophytes doesn't make sense in evolution. They are vastly energy expensive to create, while pollination can easily allow for thousands of seeds, very few of which need to survive for the species to survive.

I think a better explanation is that these are two separate symbiotic lifeforms. On Earth lichen bacteria live inside a fungus. In this more advanced composite life form the Fairy would be an animal living in a tree. The evolutionary reason for them to work like this could be that they were originally parasites that adapted to intentionally spread the seeds of their tree hosts. Eventually the trees could lose the ability to reproduce on their own, and would instead rely on the fairy parasite to spread its seeds.

In this scenario the adult fairies would likely be evolved from insects that insert their larval babies into trees, where they grow through their larval stage, and emerge at adulthood. In this scenario it is easily possible the fairies live after reproduction as well. The fairies can still emerge from the tree flowers if it evolved right, or simply cause additional different flowers to grow. (Which can give you two colors of flowers to.)


Gametophytes are usually very simple because they tend to be mass-produced.

Even if we handwave this faerie gametophyte into existence, I don't think it would have a brain large and/or complex enough to be intelligent and reach a state of self-consciousness.

The fact that those gametophytes have very short lifespans (they're born, they mate, they die) makes it even harder for them to develop humanoidism and any kind of culture. It is also arguable that for a creature to develop self-consciousness and culture, it has to meet others of its kin, something I don't see happening very often with your faeries.

And I don't even want to think about the existential horror of having my mind and consciousness being fused with another mind.

However, I love this whole idea of gametophytes being faeries and I think you could just handwave it all and everything would be fine.


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