The Japanese Horse Chestnut, Aesculus turbinata, not.

Owen Johnston has identified a tree in the Horse Chestnut collection at the front of Hadlow College as the Japanese Horse Chestnut, Aesculus turbinata.. I think that this species is really very similar to the common Horse Chestnut, A.esculus hippocastanum., but the tree identified is fairly certainly the Yellow Buckeye, Aesculus flava.

The pear-shaped(really?) fruit of pure Aesculus turbinata is without spines, although they may be warty and the hilum on the conker is much bigger than Aesculus hippocastanum, making the species easy to distinguish when with ripe fruit. There is a full range of hybrid types!

The leaves of Aesculus turbinata are a little more regularly toothed, narrower, to 40 cm, not so obviously wide above the center, and tapering more gradually to the tip. The leaflets do not have a petiolule, unlike the Indian Horse Chestnut, Aesculus indica. The underside of the leaves should be glaucous green, with hairy veins, rather than yellow green. The autumn colour is supposed to be "distinctive" - reddish perhaps. The buds are viscid. 

The flower spikes or panicles are bigger (25 cm x 6 cm) but supposedly rather less obvious, a little more "hidden" than those of Aesculus hippocastanum, and produced about 2 - 3 weeks later. The petals should be cream with red spots. 

There are two trees there at the moment, one bigger, one smaller, both in early stages of leafing out - could one of them, or both, be it?? Neither tree matches Aesculus turbinata. My best guess is that the biggest tree is Aesculus flava, and the smaller is Aesculus indica.

The interesting tree at Luddenham Court, visited in the second half of April, next to the Red Horse Chestnut, Aesculus x carnea, is quite a possibility. The leaves are already quite tattered, a bit like a Common Horse Chestnut, which I haven't seen in the on-line pictures much. however the key feature I was looking at was the absence of spines on the first stage of the developing fruit, so I was pretty sure it was not Aesculus hippocastanum.  The leaflets did not have red petiolules, so it could not be Aesculus indica, the other major possibility.  However the flowers were very white rather then cream, rather pretty and bright, and the leaves did not look that much different from Aesculus hippocastanum. Also, I didn't note any obvious glaucous underside of the leaves.