Vegetation

Grass
Grows on top of dirt blocks. A different variant can be found in the Underground Jungle, Corruption, or where glowing mushrooms grow (Blue Grass). Note that Underground Jungle and Glowing Mushroom Grass only grow on mud. If the player has a Staff of Regrowth, they can plant normal grass on dirt blocks without seeds.

Tall Grass
Grows on top of grass blocks. Can be harvested for Seeds when the Blowpipe is in the inventory.

Flowers
Grows on top of grass blocks and clay pots. While on normal grass they can be harvested for seeds just like tall grass. A variant can be found growing in the Underground Jungle. This variant can be harvested for a Jungle Rose or a Nature's Gift.

Vines
Grows below grass blocks, usually on the ceiling of caves. They block light and can be cut with any weapon. These vines are found in the Underground Jungle and on Floating Islands as well. They can have a maximum height of 10 blocks (20 feet). Vines will also block light like any other dense vegetation.

Corrupt Thorns
Grows on Corruption grass blocks in a mazelike pattern. Does 10 damage to the player (without armor). they have a maximum height of 6 blocks (12 feet). It should also be noted that Corrupt Thorns have the ability to spread the Corruption when they come into contact with grass. They can be destroyed by walking through them, though this is not reccomended. It is better to slash through them using a tool such as a hammer, pickaxe, sword or similar weapon or an axe.

Jungle Thorns
Similar to Corrupted Thorns. These grow in Underground Jungle. They inflict 26 damage to the player (without armor). They can have a maximum height of 6 blocks (12 feet).

Mushrooms
Grow on top of grass tiles. Can be used to heal 20 HP and in Lesser Healing Potions.

Glowing Mushrooms
Grows on top of mushroom grass blocks in the rocky underground levels. Can be harvested with any weapon or tool like a common Mushroom. This mushroom heals up to 50 HP and is used to craft Healing Potions and Mana Potions.

Vile Mushrooms
Grows on top of grass in the Corruption, can be used to make Vile Powder.

Bright Weeds
A yellow-greenish, spherical plant that grows in the Underground Jungle. It provides weak light that helps in navigating the Underground Jungle. Bright Weeds when destroyed, have a chance they will drop Jungle Spores.