Cassandra's mother enjoyed second grade, and would like to join Cassandra's class. She could go disguised as a plant, Cassandra suggests, and--after an evening preparing a costume--that's what she does. The ""plant"" joins in many of the class activities: climbing during recess, she's as adept as a polebean, and she acts as Jack's beanstalk when it's time for dramatics; meanwhile, a good many other characteristics of plants (some of them amusingly shared by mothers) have been good-naturedly introduced. By day's end, Cassandra's classmates realize what the teacher has suspected all along and Cassandra's mother is invited to come again. Cassandra demurs: ""...nobody's mother is in second grade. That would be ridiculous."" Pleasantly zany, with colorful, lighthearted illustrations that capture just the right tone.