Loic,
Here are 2 sibs from Pert Princess X Spell. AH69T1 has 2 stalks on the 2nd year plant. AH69T2 has 7-8 stalks and more increase. T1 is the best looking flower but doesn't produce like T2. Pert Princess is from mixed chromosomes, The cross it came from is My Fantasy (a 48c Tetraploid) X Smitten a SDB which probably has 40 chromosomes. 12-8-12-8. These mixed 'C' crosses are proving to be fertile to a degree. However, without a lab test proving otherwise I doubt they are tetraploids.
Vicki