Name means Having a petiole, not sessile

Gardens found in the 28 pre 2000 surveyed: DA  LHS EBG KEW GN WAK CBG HC LBG TR MS

Gardens found in the 10 surveyed in 2010: DA LHS EBG WS HIL  AA ESV KAL NAN JCR AA

UKPlant Finder: 2012 =  63 nurseries