Robert Dodier wrote:
Hello,

I recall from a horticulture book that I would have
read around 1978 (how time flies!) that they used the
term "clon" to mean a tree or other plant that's propagated
by asexual reproduction. ...

I think you should be looking for "clone".

cheers,

Marj
--
Marj Tiefert: http://www.mindspring.com/~mtiefert/
Mediterranean Garden Advice and Shop: http://stores.tiefert.com/garden/
In Sunset zone 14-mild