Ray Stephenson emailed me with the definitive differences between Aichryson and Aeonium

Aeonium have far more petals than Aichryson,  Aichryson are far slighter plants. Aichryson are rarely perennial.  The plant on show A. x domesticum 'Angel's Wings' has only 6-partite flowers (just checked Praeger [the bible] and he says this is so).  Aeonium usually are 8+partite but I agree on this characteristic only there could be some overlap.

 It was interesting when cytology showed Aichryson not to be unique - again there was some overlap with Aeonium.  DNA certainly does separate them with all somewhere midway between Sedum and Aeonium.  Makes one think that Aichryson could be the origins of Aeonium.  There is certainly enough evidence to show Aichryson derived from N African Sedum like S. modestum etc.  I think the taxonomists are right to keep the genus.  For identification, no Aeonium is as diminutive, so even with no flowers, it's not too difficult.

Return to the Judges' Course