Which species have you seen??? Cyrtosperma merkusii used to/does occur in
+ - 20 cultivars in the Pacific region (I have acess to two here in
Florida), some spiny, some not. Alistar Hay did a great paper on this
genus some time ago based on the knowledge he had at the time, and discussed
the spiny petioled vs. the smooth petioled forms/clones., and C.
chamissionsis, (an old Schott name as 'Arisacontis Chamissonis' ( 1897) was
placed into synonomy with it years ago.