"Mine is striped, but yours is floral."
Translation:Le mien est à rayures, mais le tien est à fleurs.
Note that it is à rayures, also (no articles, rayures is plural). In this construction (à xxx) the phrase acts as an adjective. Lots of prepositional phrases in French do not take articles. In this usage, à does not. Obviously, à does take an article in many other situations.