"convergent": You probably meant "convergently".
I suggest you remove those tiny white specks between the bubble seeds of some branches, although they are so small this is optional.
"due to its ancestor's branches" Can you clarify what you mean by this? I suggest: "its ancestor's branches occasionally were knocked down, and as it split off from its ancestor, it consequently developed a countermeasure against the branches being knocked down."
"floating It". There's a missing period.
"hydrogen filled" I recommend: "hydrogen-filled".
Things in the template at the top are generally capitalized.

Unless its bubble-leaves are different from is ancestor's, I recommend clarifying the shape of the bubbles. Right now, they look kind of like Hawaiian halfflowers or stylized baobabs.

Are there conditions where its bubble-leaves don't float? It would appear such, judging by one branch's tip facing downward.

While functional at its size, a little more detail could improve the description, such as the function of the onion-flavored bubble seeds

The bubble leaves are anchored to the tree and can no longer float.

"The hydrogen bubble seeds taste somewhat like onions to ward off herbivores, but this survival tactic did not work on specific species." If it didn't work, not even a little, why did it evolve? You can always say that, while herbivores do eat it, the onion taste makes it less preferred, so they eat less of it, or it is largely effective as a feeding deterrent against major pest genus groups (e.g., Minikruggs).

Support is cellulose cell walls if purple flora
Respiration is passive stomata if purple flora
Thermoregulation is Ectotherm if purple flora

Unless otherwise elaborated on, I think.

"Its ancestor's branches occasionally being knocked down, no longer leaving the branches floating." This sentence needs to be revised.

It would help to specify the shape of the branch-tips. Shading could help with this.

Anything now?

Approval Checklist:
Art:
Art Present?: Y
Art clear?: Y
Gen number?: Y
All limbs shown?: Y
Reasonably Comparable to Ancestor?: Y
Realistic additions?: Y

Name:
Binomial Taxonomic Name?: Y
Creator?: Y

Ancestor:
Listed?: Y
What changes?: Thicker stems, tastes like onions, flopped stalks
External?: Y
Internal?: Y
Behavioral/Mental?: Y
Are Changes Realistic?: Y
New Genus Needed?: N

Habitat:
Type?: 1
Flavor?: 2
Connected?: Y
Wildcard?: N

Size:
Same as Ancestor?: N
Within range?: Y
Exception?: N/a

Support:
Same as Ancestor?: N
Reasonable changes (if any)?: Y
Other?: Clarifying

Diet:
Same as Ancestor?: Y
Transition Rule?: N/a
Reasonable changes (if any)?: N/a

Respiration:
Same as Ancestor?: N
Does It Fit Habitat?: Y
Reasonable changes (if any)?: Y
Other?: Clarifying

Thermoregulation:
Same as Ancestor?: N
Does It Fit Habitat?: Y
Reasonable changes (if any)?: Y
Other?: Clarifying

Reproduction:
Same as Ancestor?: Y
Does It Fit Habitat?: Y
Reasonable changes (if any)?: N/a
Other?: N/a

Description:
Length?: Okay
Capitalized correctly?: Y
Replace/Split from ancestor?: Split
Other?: N

Opinion: Approved