Plants and Trees is an inherently unlocked research in the Basic Information tab.It details the 5 different plants and trees added by the game, there being 3 plants and 2 trees and them being: Shimmerleaf, Cinderpearl and the Vishroom as plants, and Greatwood and Silverwood as trees.
The Greatwood Tree can be found in almost any biome where trees can grow. They are relatively common, and grow to mammoth sizes, being visible far above any other tree in the game, and yielding massive amounts of wood when cut down. The logs and branches can catch fire, but do not burn up. Like any other tree, their logs can be crafted into wood, however, logs yield 4 planks each, and they also drop saplings. Only one must be used to grow the tree, which has a 2 by 2 wide base. Naturally generated Greatwood Trees have a chance of spawning with cobwebs scattered around the branches and a monster spawner underneath with a chest beneath itself filled with random loot. Greatwood logs and planks are both used often in Thaumaturgy, serving as crafting components and building blocks.
The Silverwood Tree is a relatively large, and quite distinct, tree that can be found, rarely, in most biomes, excepting for the Magic Forest biome, where they are quite plentiful. It has a large base, and can grow to be shorter and stouter, or large and skinny, with very pale wood and blue, shining leaves. Like the Greatwood Tree, Silverwood behaves much like a normal tree, dropping sapling, albeit quite rarely, usually only one or two per tree at most, and being grown from only a single sapling. Also, the tree cannot be destroyed by fire, or catch fire. Silverwood has any uses in Thaumaturgy, but can also be used as a building material. The trees themselves are also unique, being the only way to add more Nodes into the world through their property of being able to create Pure Nodes within themselves when they finish growing, albeit not always.
Shimmerleaf are small, pale blue flowers with silvery, glowing bulbs at their center. They can be found around the base of naturally generated Silverwood Trees and are usually easy to find, especially with their glowing properties. The flowers can be used to create Quicksilver, and also have a few uses in crafting. Specifically, they can be used to make the Ethereal Bloom, a magic flower that can be used to guard areas, about 8 blocks in every direction, from the effects of Taint. However, this has no affect on the Aura itself, and can be considered more of a treatment of the Symptoms of Flux than the malady itself. The flowers can also be used as decoration.
Cinderpearl are small, dry looking flowers with what appear to be burning bulbs at their center. They can be found in only the "hottest of biomes", such as deserts and mesas, and have no use except for decoration, and to be harvested and crushed to create blaze powder. They are plentiful in areas that they grow, and as so are a great source of the otherwise relatively difficult to obtain blaze powder. Because no way exists to convert blaze powder back into blaze rods, Cinderpearl has few uses before one has traveled to the Nether and begun brewing.
Vishroom have no inherent use, other than being able to be broken down into Essentia, and can only be found in the Magic Forest biome. They can be easily spotted due to their bright color and the fact that they glow and shimmer. However, it is advised not to touch them, as entering into the same block as them causes 5 seconds of nausea, however, because the duration is so short, one has little time to actually experience the effects unless the Vishroom is stood on for several seconds.