homage or plagerism ?

Irving Penn's "Flowers" was a landmark book that ever changed the way photographers looked at flowers. The book which has been long out of print is a classic and a prized item on the bookshelf. Last night I was at a local bookstore where I saw stacks of a similar book by a japanese photographer. The cover, contents, and the format of the book was so similar that I wondered if it was a homage or just plain plagerism. We all immitated and have been influenced by Mr. Penn's photography style at one point but I would be so embarrased to publish something that looks so similar without the magic of the original master.