The genres are: Classics, Picture, Traditional, Historical Fiction, Fantasy & Science Fiction, Folktales, Nonfiction/Biography/Autobiography, Fiction, and Poetry. 
 
Classics are any book that was published on or before 1950.  An example would be the Laura Ingalls Wilder's series.  Picture books are any book that has a value of 50% are in pictures.  You take the pictures out of the story and the story wouldn't make sense.  10% of the book gets split in half between the illustration and the author. 
 
Traditional books can also be picture books.  Caldecott books are picture books.  The characteristics of traditional books is that it is usually a story that has been passed down by mouth from generation to generation.  Folktales as well as mythology, Indian legends, fairy tales, and Bible stories are all a part of traditional books. 
 
Historical fiction are books that are fictional stories put into actual history surroundings.  You would be able to teach history from it because the author has carefully researched that period and paints a picture of that period through the writing. 
 
Fantasy is a story that couldn't happen in the date it was written.  The reader could ask the question, "Could this story really happen in the date that the story was written?"  If the answer is "no," then it is fantasy, if the answer is "yes," then it's historical fiction.  Science fiction is fantasy set in the future.  "Fantasy books have talking animals, supernatural beings, and parallel worlds woven together in a time and place where all the story elements seem possible."  (Moen, 94, Scholastic, Teaching with Newbery Books).   
 
Folktales are part of traditional stories, they have one-dimensional characters, are often humorous, explain nature or the culture in which we live. 
 
Nonfiction provide facts and information about the world we live in (also past).  Nonfiction includes art (history, artists, how-to-draw, etc.), drama (folk play, Shakespeare), language arts and literature (libraries, newspapers, word play, writing), math, music (famous musicians, how to, opera, song text picture books), social studies (economics, geography, history, people, politics).  Biographies are factual accounts of different people's lives.  An autobiography is a factual account of a person's life from that person's point of view. 
 
Fiction is imaginative narration, a made-up story. 
 
Poetry is a rhythmical composition (in verse characterized by artistic construction and imaginative or elevated thought).  The written composition is used to excite pleasure by beautiful, imaginative, or elevated thoughts.  Children's poetry consists of topics that relate to children, have children as the main character, and/or touches the child in the adult.
 
I hope this helps, I can go into more detail if you need that, let me know personally. 
 
Dee