Since the beginning of recorded history, mankind has depended on nature to survive. Plants produce the oxygen humans breathe, and in turn feed on the Co2 produced by humans. Nearly all of the food humans depend on either comes from plants, or from another animal which also feeds on plants.
In the early 21st century it was discovered that plants were genetically twice as developed as humans, as well as the fact that root structures bore a striking resemblance to animal neurons. Yet, against all scientific logic plants remained passive and without conscious thought.
In recent times though, a strain of plant life has reached the level of sentience. It was no mysterious and inexplicable appearance... no, this was well documented. Scientists in the Omicrons attempted to combine a human being with plant DNA. The result however was for more than they expected. These experiments activated genes in the plants which had been dormant for eons, granting the plants affected the capacity for sentience.
This "spark" of sentience spread like wildfire, infecting any and all plants it came in contact with like a virus. Since the most developed DNA will always consume less developed strands in a body, the plant DNA overwhelmed its human host. After some time nothing was left of the human test subject, except her memories and emotion... What some would call her "soul".
That fire continued to spread, leading to the birth of a race which had lied dormant like a sleeping dragon for countless millions, perhaps even billions of years.
In nature there is great variety. We are one cause but many forms. We grow and we adapt, and along the way new forms appear.
The Touched.These are the humans who have been blessed with the spore. Our seed is planted in their brains and its tendrils grow down into their flesh. They willingly give us their minds and hearts. we consume their sorrow and anguish, and fill them with love and contentment in return. Their life enriches our own sentience. They exist in many human factions, and continue with their various occupations after being touched. They spread the spore to their kin and colleagues, and plant gardens on their home worlds.
The Gatherers.There are stories among the plants of vicious, monstrous beings called the Gatherers. They are mythical beings said to travel abroad harvesting human beings and any other creature that makes itself harmful to nature. The legends say that once they have collected a group of beings, they are taken back to the middle of the largest forest, and consumed. Their bodies are eaten, but their consciousness is transferred into other plants, so that they may fill a new role in nature and repair the damage they did. There is no tangible evidence that these creatures exist, and the general consensus of the forests is that they are nothing more than a legend.
The Forests.The spark of sentience that inhabits the plant life produced by our seed. Those who have transcended their physical bodies become part of the pool of consciousness within the roots of the forests. When the bodies of the touched expire, they remain here. The Gatherers bring those wayward souls that have been culled deep into the forest where they spend the remainder of their days in bliss. Each time a new mind becomes one of these, a new forest must be seeded. Each forest can expand to encompass an entire world.
Identity These plant-creatures have yet to identify themselves by any specific name. Often the first sign of their presence visible to humans is the spores that they sometimes use to reproduce and spread. Thus they are referred to as "The Spore" by many. Naming individuals with a single word is a human tendency however and these plants seem to feel no need to apply such a word to themselves, so they remain nameless.
Physical attributes These creature's sense of individuality is somewhat blurred from a human perspective. Each independent mind is formed by the interlocking root-neurons from hundreds or thousands of individual plants. Essentially, one forest of these plants is one "person" with its own feelings, thoughts, and ambitions. When multiple forests inhabit one planet it is nearly impossible to tell where one begins and another ends, except by asking them.
Culture The culture of these Forests is constantly developing, though it is centered around growth and nature. They view themselves as the incarnation of nature, meaning that they have an inherent right and obligation to spread and cultivate life in every way they can imagine. Terra-forming is an almost religious thing to them, an insatiable and powerful desire to transform every planet they find into a lush paradise governs their actions.
Habitats Early in their development, the creatures came across planet Primus in the Omicron Kappa system. Seeing the potential benefit, the Primusian Apes gave permission for these entities to plant seed on their world. A vast battlefield littered with bodies has been transformed into a forest which rivals Gaia in sheer density of life. The bones of fallen soldiers now supply these fast growing adaptable plants with high amounts of calcium.
See: Seeding of Primus
The Crucible Little is known by outsiders about this structure. The Primusians built it upon the request of the forest, it is a massive bio-dome in the center of the forest on planet Primus. The dome shields the contents from the harsh ambient radiation on Primus, allowing an environment hospitable to humans, though no outsiders have ever been allowed to enter. Strange rituals are thought to take place inside, the purpose and nature of these is unknown. All sentient forests contain a similar but smaller version of this structure, including colony ships.
Seed Ships Many of the forest entities live nomadic lives, traveling through the stars looking for more worlds to settle on. To do this they need massive ships to carry large quantities of seed, and also living plants in sufficient mass to constitute a mind large enough to control a ship. All knowledge these plants have on ship building comes from the Zoners, the only largely space-faring group to acknowledge them as sentient beings. Through their connections in the touched, the plants are able to gather materials for ships and construct them with the help of the Primusians, who are reimbursed with organic tools and weapons, as well as food.