Marbubble

While the marbubble looks identical to its ancestor, marbleflora, their insides have changed considerably. A large chamber filled with lighter-than-air gasses dominates its interior, allowing it to float around in the atmosphere. There, it thrives due to the lack of competition. However, it cannot survive off of photosynthesis alone. because of this, numerous pores cover its surface that are connected to shallow pits that don't reach the central chamber. Inside of these pits are numerous hairs that capture and digest airborne microbes like nimbuses. They convert almost all of their surplus nutrients into lighter-than-air gasses in order to remain afloat. Unfortunately, this means that whenever they need to reproduce, they must return to the surface because their surplus nutrients are being used for reproduction rather than gasses. Once landed on the surface, they start to absorb as many nutrients and water from the ground as possible and turn those materials into buds or spores. If it buds, the buds will split off of their parent to start their lives of floating around in the atmosphere; and if the parent bubble is lucky and is not eaten or 'popped' by being stepped on by an unwary animal or eaten by an herbivore, it too will float off into the atmosphere. However, if it produces spores instead of buds, the central chamber will fill up with spores until it bursts, killing the plant. The spores are light enough to be easily carried by the wind and will start to grow in the troposphere. Young spores will quickly grow their central chambers and fill up with gasses as soon as possible before it becomes too heavy to float around without a chamber. These plants are incredibly fragile and can easily be popped by sharp objects or by somehow being squashed. This is why they need to produce quickly and in large numbers.