An aesculus.

As you can see I'm working on adding more pics to my site.

Part of that is finding the right botanical names for various pics.

So here's a very interesting horse chestnut: it has the normal horse chestnut (Aesculus hippocastanum) leaf, and rather pretty horse chestnut flowers, but the seedballs are smooth. No spikes.

Weird.
Here's two pics:
Pic: Very pretty flowerspike with unripe (and still furry) seedballs.
Pic: Branch in flower.

What sort of horse chestnut is this? A cultivar, or a hybrid with something else? Many thanks!