I also know a place near my home in Germany where I found a lot of 4 leafed, 5 leafed and 6 leafed clovers. It was interesting, that it seemed that there were more 5 leafed than 4 leafed. It would be worth to collect some seed and sow it. I digged out some 4 and 5 leafed plants but in my garden they only develope only three leafes. It seems that it is not a genetical thing but more a subject of the surrounding conditions.

As an 12 year old I found sixty four 4-leaf clovers one afternoon. I remember having my sixth grade science book stuffed with 4-leaf clovers I was always drying. Also as a child I found leaflets numbering up to thirteen! If you find one 4-leaf clover (or any number of multiple leaflets for that matter), you should trace the runners of that same plant and you are much more likely to find more four leafs.

I came to associate a greater likelihood of 4-leaf clovers on plants of a certain leaf marking and leaflet shape, which makes it easier to spot them. Oddly enough, I can't recall which marking they were--but I think it was where the white bars form a heart shape or are at least flattened where they meet at the midvein (as opposed to the white bars forming an oval or arch where they meet at the midvein. The more likely leaf shape also tends to be kind of nipped inwardly at the midvein, making the leafelt also tending to be heart-shaped or flattish on the outermost edge.

It also seems like there was a relationship between how "broken" the bars were and how likely it was to find a 4-leaf. I'm sorry, though, I'm really rusty on my clover hunting and do not remember with certainty what it was that I used to look for.

Hope that description makes sense. If you can train yourself to look for those sorts of leaves, I think you can find the 4-leafs more easily. I used to bet people I could find a four leaf clover when we stood over such a patch of clover and usually I could find one within five minutes. You get to the point where they nearly jump out at you, even when you aren't trying. The pattern just presents itself.

I have some information about the genetic diversity in white clover if you are interested. But I'm afraid it does not focus on leaflets, much as we would like such a study.

If you want to ask me anything, please send me a message through the GardenWeb mail. I'm not sure when I would otherwise be back to this forum. But I'd be happy to answer you here on the forum.