Depending on its generic circumscription Staphylea counts ca. 10 or more species in temperate Eurasia and North America (Mabberley 2008). At least four species are cultivated for ornament in Europe (Wann 1997). S. pinnata is the most known of these ornamentals but according to most authors it is decreasing now in gardens, in favour of S. colchica (e.g. Weaver 1980, Sell & Murrell 2009). The latter has larger, showy corollas with a pleasant Citrus-like fragrance. The identity of each individual Staphylea population in Belgium needs to be critically re-assessed. However, all specimens documented so far seem to pertain to S. pinnata. Some plants in cultivation are hybrids between these species with more or less intermediate features (see Weaver 1980). They are best referred to as S. ×coulombieri André.
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Sell P. & Murrell G. (2009) Flora of Great Britain and Ireland. Vol. 3 Mimosaceae – Lentibulariaceae. Cambridge University Press, Cambridge: XXVIII + 595 p.
Wann J.D. (1997) Staphylea. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 5. Cambridge University Press, Cambridge: 180.
Weaver R.E. Jr. (1980) The bladdernuts. Arnoldia 40(2): 76-93. [available online at: http://arnoldia.arboretum.harvard.edu/pdf/articles/1980-40-2-the-bladder...