Much of the story of Marimite revolves around the Yamayuri Council (Yamayurikai, lit. "Mountain Lily Council"), which acts as the student council. The Yamayuri Council meet in a building called the Rose Mansion. Located within the school, it consists of two stories, including a meeting room on the second story.
The Yamayuri Council itself consists of three offices, named after roses: Rosa Foetida, Rosa Gigantea, and Rosa Chinensis.These are also referred to by their colors; the Yellow Rose is Rosa Foetida, the White Rose is Rosa Gigantea, and the Red Rose is Rosa Chinensis.
A Rose, or Rosa, is one of three senior members of the Yamayuri Council, although it is also possible to generally speak of all the members of the Yamayuri Council as roses. A Rose makes the important decisions within this group, since she has control over the student council. Candidates for the position, which lasts through the school year, are chosen through an election. Any student can run to become a Rose, although the position is usually given to the en boutons, the Roses' petite sœurs.
The petite sœur of a Rosa is called an en bouton, otherwise known as bara no tsubomi. En bouton is French for "in bud" — as used in the example Rosa Chinensis en bouton — and is unofficially considered part of the Yamayuri Council, as is the petite sœur of the en bouton, if she has one. The en boutons must be in a lower year than their oneesama, and generally the en boutons execute the plans discussed by the Roses, like assistants. Although the Rosa positions of the Yamayuri Council are traditionally passed to the en bouton on the graduation of the current holder, they are nonetheless elected offices which anyone may run for.
The petite sœur of the en bouton is called en bouton petite sœur — as used in the example Rosa Chinensis en bouton petite sœur — and is otherwise known as bara no tsubomi no imōto. She must be in a lower year than her oneesama and performs small duties, such as attending to the Roses' en boutons, cleaning the Rose Mansion, and making tea and snacks for the Yamayuri Council. This lasts a school year, and the following year, when their oneesama is elected, the petite sœurs become en boutons automatically.
The Yamayuri Council is comprised of three rose families:
This group is parodied in the anime "Beelzebub" in episode 51 with the group Taniyurikai