Misc: Kind of skin inflammation?

Questions

Common name for a plant family, & for plants of the family's typical genus?

Common name for a plant of the sedge family?

Common name for a small family of aquatic flowering plants, & for its representative genus?

Common name for a small family of trees, widespread in the temperate areas of the northern hemisphere, & for its representative genus?

Common name for a small family of woody flowering plants, & for certain trees of its representative genera?