Bulbochemophyta

Bulbochemophyta (meaning 'round chemical plant') is the clade containing all advanced chemotrophic multicellular organisms with an alternation of generations life cycle.

Bulbochemophyte evolves from ancestral multicellular chemotrophic organisms known as the chemophytes that are very specialized in chemosynthesis, able to sustain themselves without needing other sources of nutrients or energy. Some of the bulbochemophytes, however, required other methods of acquiring nutrients or energy due to their unique life cycle. Their populations are higher in the southern hemisphere, with the highest concentration near the gigantic volcano.

By floating on the water surfaces, they are sometimes trapped in the intertidal zone, which could lead them to be one of the first land colonizers which could change everything.

Anatomy
Unlike the bulbozoon lineages, bulbochemophytes derive from another group of microbes that are specialized in chemosynthesis that forms colonies on water surfaces, which over time, their bodies evolve be radially symmetric. Though similar to bulbozoons, they have mesohyl.

"Leaves"
Although evolved independently, bulbochemophytes evolve a ring of fins on the top part similar to that of phyllostomes. Unlike the phyllostomes, however, they are used to increase the rate at which the hydrogen sulfide is taken in. However, being directly exposed to the air means the water is easily lost. The bulbochemophytes respond by evolving a cuticle layer in addition to a thick epidermic cell layer to prevent water loss while having pores that can be opened or closed for gas exchange.

Counterweight
To maintain the upright position for the leaves, bulbochemophytes evolve tendrils on the underside as a weight. Some species have short yet very thick tendrils with high density while some others have very long tendrils.

Behavior
Bulbochemophytes don't have any particular behavior as they lack any nervous system. They normally float on the water surface, fixating carbons for their lifetime.

Reproduction
From directly evolved from microbes, bulbochemophytes can reproduce asexually, either from budding or fragmentation. However, they are also able to reproduce sexually. Though unlike bulbozoon lineages and unique to them, they have an alternation of generations, which means that the adults, or the sporophyte, will release numerous spores of both gender into the water that sink to the seabed, which then develops into a patch of megagametophytes and microgametophytes. The gametophytes, after a certain time of development, release the gametes into the water again. The egg cells float on water, making them rise to the surface quickly. After fertilization, the zygote develops into the bulbous plant that floats on the surface. The cycle then continues.

Gametophytes
The gametophytes of bulbochemophytes look nothing like their sporophyte form. Each gametophyte is either a megagametophyte(female) or microgametophyte(male). Both types of gametophytes possess a large amount of red photosynthetic pigments that evolved from symbiotic microbes in their leaf tissue to perform photosynthesis as the gametophytes are normally fully submerged, limiting them from performing chemosynthesis. The microgametophytes have a single branch on a bulb that supports both a flower-like gametangium and two large leaves. The megagametophytes have a branch that supports a flower-like gametangium, similar to the male gametophytes. However, four leaves grow from the bulb directly instead of on the branch. Also unlike the polyphyllophytes who are capable of photosynthesis like the gametophytes, they don't have a cellulose cell wall, making them squishy and an easy food source. This is countered by the enormous spores that become massive patches, increasing the chance of the gametophyte survival by the sheer number alone.

Competitors and Predators
From them being an autotroph, Bulbochemophytes compete between themselves and the million microbes in the sea for sunlight, carbon dioxide, and hydrogen sulfide. The sporophytes are rarely eaten due to them floating on the water surface, creatures coming to eat parts of bulbochemophytes would risk their life on doing so as they might get spotted by a predator.

This is not the case for the gametophytes, however, as they form a large patch underwater. Small creatures normally take refuge in the dense patches for protection. While some larger creatures, such as pachypterids, sometimes take a bite on the gametophytes' leaves. Sometime later, a small creature that feeds on the sessile organisms and debris emerges.

Diet
Due to them being autotrophic in origin, they never "feed" on other organisms but instead taking in hydrogen sulfide found in the atmosphere to be used in the chemosynthesis. They are also partly phototroph.

The gametophytes, however, are mainly phototrophs due to them being fully submerged underwater, which limiting them the amount of hydrogen sulfide to be used in the chemosynthesis.

Distribution and Habitats
Bulbochemophytes can be found in the southern hemisphere floating on the water surface. They are at the mercy of water currents, meaning some of them may get led astray onto the northern hemisphere, though they are struggled to survive there due to the less hydrogen sulfide on the northern hemisphere. The gametophytes, however, are in a different situation. The gametophytes mainly live on photosynthesis, making them only able to proliferate in the shallow water.