In article ,
"FarmI" ask@itshall be given writes:
|
| The sloe has 32 chromosomes, the myrobalan (P. cerasifera) has 16 and 'a
| freak combination of the two has been shown to occasionally give a plant
| like P. domestica, with its 48 chromosomes'.

Yes. A chromosome doubled hybrid. Probably natural, but we don't
know for certain - any more than for wheat.

The abstract I referred to said that the sloe itself is a natural
chromosome doubled hybrid between P. cerasifera and P. microcarpa.

| P. insitia also has 48 chromosomes and within this group are the bullace,
| the damson, the mirabelles and the St. Julians. ...

Nowadays, all (?) authorities agree that P. institia is just a subspecies
of P. domestica - if that.

| There is also an interesting discussion on archaelogical finds of plum
| stones and that 'no domestica plum stones...have been found under the ashes
| of Pompeii' and that the plums mentioned by Pliny (who wrote of the plum
| from Damascus)were 'all insitias, or if domesticas, were recent
| introductions to Europe'

In other words, the large-fruited hybrids are recent. Not all that
surprising, really.


Regards,
Nick Maclaren.