I found a teeny tiny cleome seedling this morning in a bed that had cleomes in it last year, so can post a couple of pictures to show what they look like - sorry for the picture quality, taken with my phone which doesn't do macros very well especially on things this small.
The first shows the seedling - the green thingy to the right is a fertilizer granule from last year (off to the side so not visible in the thumbnail) so that gives you an idea of the small size of the seedling and that it shows leaflets even at this early stage:
This shows the cleome seedling next to a recently planted cleome that is still only about ten inches tall itself:
