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Homatripalis (Tribusicorpora spp.) [Three Bodies]
Creator: Salty
Ancestor: Homashidis
Habitat: Talon-Dixon-Fermi, Dorite Island
Size: Sporo (5-15m), Female (1-10m), Male (50cm-5m)
Support: Woody trunk
Diet: Photosynthesis (Sporo: Full Sun, Gam: Partial sun)
Thermoregulation: Ectotherm
Respiration: Passive (stomata)
Reproduction: Sexual (Metagenesis, spores)

Homashidis diversified rapidly following the End-Binucleozoic extinction, with a myriad of species adapting into new forms. Homatripalis took to growing larger and foresting its region much as their Busrota and Busromble cousins before the extinction. However, where their extinct cousins integrated their gametophyte stage into the sporophyte, Homatripalis have diversified each stage independently.

The sporophyte stage of Homatripalis is always the largest of the life stages, followed by the female gametophyte and then the male. The female stage also has a much thinner trunk than its other life stages. Apart from these differences, each stage has similar morphology. The Sporophyte stage is the longest lived, with some species lasting 80 years. Female gametophytes range from 10 years to a single year, and the majority of male gametophytes only live for a single growing season. Differentiation between species is based predominantly on the number and distribution of frond rings. Tropical and Subtropical species tend towards a higher concentration of frond rings near the crown of the trunk, whereas Temperate and Subpolar species tend towards more evenly distributed frond rings.

"diversified each stage independently"

Would this be best described as the gametophyte having become dioecious within the gametophytes? Could you add "dioecious gametophytes" somewhere in the reproduction section?

Is it practical for the genus group to exist with sporophytes and gametophytes all at large sizes, apparently existing detached from each other? In ferns, the gametophyte, while free-living, is much smaller than the sporophyte. If the majority of male gametophytes live for only a single growing season, that might be difficult to do in polar or subpolar latitudes of Fermi. Certainly, some living things have very short-lived males (fig wasp males die in the very figs in which they hatched), but the fact these are flora means they are rooted in place, and can potentially be eaten before reaching maturity.

I know the sporophytes produce spores, but I wonder how the gametes from the gametophytes reach each other. They seem too far away for the male gametes to swim over. The reproductive method of the Homosaraetes (Homashidis' ancestor) suggests a sort of "wind-pollination", but this is useful to specify here.

One way to justify the gametophytes and sporophytes being independently-living, huge, and apparently far away from each other is for them to sprout from roots or rhizomes, or to receive nutritional support through an interconnected root system. The system still seems impractical, though.

It's worth specifying what kind of environments they live in. It seems very unlikely they could live in Talon Hot Desert if the gametophytes only live in partial sun, for example. Judging by the minimum sporophyte size, it seems unlikely it could live in Sky Alpine, and probably not other rocky, high-altitude habitats, either. Other details about their reproduction would also be useful.

Morphologically identical sporophytes and gametophytes are common in algae in real life. No reason it can't be the case with a large land plant.

A large land flora gametophyte may take more time to grow, which means more time for it to potentially be eaten by herbivores and so be unable to reproduce. Consider oak trees: they grow huge, they grow old, and they have defensive compounds in the form of tannins. Something like a henbit plant, a short-lived (cool season ephemeral) weed, does not have defensive compounds, grows fast, and reproduces at a small size.

Of course, the practicality of responding to herbivores depends entirely on there being herbivores for this species. It may very well be that they can afford a risky life configuration in most environments, simply because it's after a mass extinction event, and what herbivores left don't eat it or its ancestor. It would have the practicality of a dodo: they don't need anti-predator adaptations because they have no predators.