Hi Patricia, thanks for your reply.
There is not much colour in my plant. Flowers are white to faint pink, however they are very double and brunonii flowers are not double.
But your expression "the seeds of which come up like grass" characterizes this plant quite well.
;-)
Actually I overlooked the earlier posting from Wernersen from Berlin having seedlings of PHM as well.
Seedsetting and germination here in Germany seems to be not a rare event.

As mentioned in these posts it might be that PHMs offspring is simply not that interesting and not worth talking about.

So I am going to keep the seedlings but without special care. Survival of the fittest.