In message , Bernhard Kuemel
writes
Hi sbb!

I discovered purple walnuts:

http://bksys.at/bernhard/img/x27/dscn5930.jpg

I'm impressed. Are they well known, or shall I trace their source
(maybe from one of our trees) and give some to ppl to cultivate them?
Can they grow when already opened? How would you best germinate them?

Bernhard

Google finds a Juglans nigra 'Deming's Purple', with purple kernels, but
I don't suppose that's all that common in Austria. Also, a mention of a
planting of a purple walnut in England, but no mention of species.

The RHS Plantfinder mentions Juglans nigra 'Purpurea' and Juglans regia
'Purpurea', and also Juglans 'Red Danube', which might be the same as
Juglans regia 'Rode Donaunoot'. No immediate indication of kernel
colour.

More digging finds Livermore Red Walnut, which has "vivid red" kernels.

You could try contacting one of the nurserymen that sells the purple
form and ask whether the purple colour of this extends to the kernels.
--
Stewart Robert Hinsley