Sort of depends upon the seedling when it occurs. The arachnoideums seem not to do this and it is the same in their hybrids. Ditto the velvety ones.
Lots of my 1 year old seedlings show watermarks but it's more obvious when they are more mature. There's lots of 'Jungle Shadows' kids that show this pretty early on.
It adds lots of interest in my crosses.
Kevin
