Misc: In 1950 Chinese troops crossed the 38th Parallel in---------- . ?

Questions

Common name for a medium-size family of mostly woody flowering plants widely distributed in tropical areas, & for its representative genus?

Common name for a number of species of water birds of the same family as ducks & swans?

Common name for a plant family comprising about 227 genera & 4450 species of mostly temperate herbs, & for its representative genus?

Common name for a plant family with about 50 genera & 1300 species?

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