To have some hard info: T clusiana with T linifolia and montana forms a separate subgenus in Tulipa. the other subgenera : Orithyia, Tulipa, Eriostemones T clusiana f cahmeriana is diploid (including aitchisonii) T clusiana f ...is triploid ( examples: Sheila, Taco, Tubbergens Gem) T clusiana f dinae is tetraploid.examples: Tinker,Lady Jane, Cynthia) T clusiana f clusianae is pentaploid Ben -- BJM Zonneveld Naturalis, Herbarium section Postbox 9517 Darwinweg 2, 2300RA Leiden The Netherlands Email: ben.zonneveld@naturalis.nl <Ben.Zonneveld@naturalis.nl>, telf 071-7517228