Yellowstone has a larger number and variety of plants than anywhere else in the continental United States. Here's are some of the most common varieties:

Lodgepole pine (Pinus contorta)
The most common tree in the park, this is a straight, tall pine reaching up to 75 feet. Some Native Americans used it to frame their teepees or lodges. It grows in thick groves where lack of sunlight prevents lower branches, and monopolized 75 to 80% of Yellowstone's forests.

Engelmann spruce (Picea engelmannii)
This spruce thrives in areas with volcanic soil.

Fairy slipper (Calypso bulbosa)
Also known as the calypso orchid, it includes 12 orchids found in the park. It blooms early and gets its common name from the fact that the blossom looks like a fairy slipper. The orchid is found in shaded areas of the coniferous forest.

Wyoming Paintbrush (Castilleja linariaefolias)
This is one of 200 species of Indian paintbrush plants found in the United States. It gets its name from a native American legend about a brave who was trying to paint a sunset and threw down his paintbrush in frustration. The plants then grew where the brush landed.