Give some stream of consciousness and then the answer. The Tudor rose (sometimes called the Union rose) is the traditional floral heraldic emblem of England and takes its name and origins from the House of Tudor, which united the House of York and House of Lancaster.

Based on this passage, emblem which united houses of york and lancaster?
To answer this question, we should know that: The Tudor rose (sometimes called the Union rose) is the traditional floral heraldic emblem of England and takes its name and origins from the House of Tudor, which united the House of York and House of Lancaster.
Therefore, the answer is The Tudor rose ( sometimes called the Union rose ).