Thory, the botanist who wrote the text for Redouté's Les Roses, classified Damasks separately from Biferas based on the receptacle or seed pods of the plants. He set out the differences between Damasks, Biferas, Albas, and Centifolias as follows:
R. damascena: receptacle swollen towards the middle and narrowing at both ends.
R. bifera: receptacle funnel-shaped, confluent with the pedicel.
R. alba: receptacle ovoid, globose at the base, like an inverted thimble
R. centifolia: receptacle ovoid, globose at the top; pedicel much longer; petiolar prickles absent