Plants within the rainforest are divided into five rough zones, corresponding to height, and therefore access to sunlight. The dominant competition in the forest is over access to light, leading to adaptations to reach sunlight or tolerate shade. Poseidon rainforests are much like Earth rainforests, though they are generally taller by on order of three or more.
The emergent zone consists of widely spaced trees, 100 to 120 meters in height, with an umbrella-like canopy extending above the general canopy around them. They must bear drying winds, so most have tiny leaves. Emergents faced with seasonal dry spells are often deciduous, shedding leaves during these seasons. This is more common at subtropical latitudes.
The bright canopy is a closed canopy of 90 meter-tall trees. Full sunlight falls on this layer, but is then blocked from lower levels. Trees of this and lower layers often have drip tips, extensions of the branches that encourage transpiration by exerting a drawing force.
The dark canopy is another closed canopy of 66 meter-tall trees. Air currents are sluggish in this layer, causing a great deal of humidity. Trees of this layer often have very large leaves to capture what light they can, and a tall, conical crown.
The shrub/sapling layer is marked by very little light. Less than three percent of the light from the top of the forest canopy reaches this layer. Saplings are common, stunted and doomed unless a hole appears in the canopy. If this opportunity arises, the sapling will then grow rapidly to fill the available niche.
Saplings often exhibit many of a layer's specific strategies as they grow within that layer. For example, an emergent tree at the dark canopy layer will often have broad leaves and drip tips.
The ground layer has very few plants. Only one percent or less of the light from the top of the for est reaches the floor. The ground layer is also less humid, with only two-thirds of precipitation reaching the ground. The rest is absorbed at higher layers.
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