Aesculus hippocastanum - Horse Chestnut

The horse chestnuts are a moderately fast growing deciduous tree to about 50' by about 40' wide. Often oval to oblong shaped or a broadly spreading habit, they create a very dense canopy and dense shade. Beautiful in bloom and usually great fall color. They also have great flowers early spring. This one is in Cambridge England. They are a pretty old-school tree and I don't see them around our area.

Leaves are opposite and palmately compound with 5 leaflets. The center leaflet is generally quite a bit larger than the others. Leaflets are 6-8" long by about 3" wide, obovate shaped with with a slightly drawn out tip and serrated margins. Veins uniformly spaced off the midrib and deeply set in the foliage. 

When just emerging from the buds, the young leaves (petioles and some of the undersides) have a rusty tomemtum near the leaf blade attachment.

Flowers are very attractive, in upright clusters 8-12" tall. Individuals are white with a blotch of yellow that turns red in the throat.

Fruit is an attractive green leathery husked capsule with sharp spines,  2 1/2" diameter releasing 1 or sometimes 2 brown shiny seeds.

Fall color can be spectacular. Often less that so here. Usually more yellow that orangish yellow in this picture. I am a bit surprised I don't have a better picture of this tree during the fall or in flower.

Stems are large and have distinct leaf scars. Buds are sticky. Leaf scars are large, and you can easily see the vascular traces forming a U.

Bark is grayish brown in small shallow irregular shaped scales when old, smooth and gray when young.

There is a double flowered form 'Baumannii'.

Misidentification: Other buckeyes, at least around here you will find A. x carnea more often than A. hippocastanum. A. carnea has dry buds, not sticky, red flowers, smaller leaves and shorter more rounded habit.

Location:
Aptos - Cabrillo College, by the Sesnon house down the side of the hill towards the creek. Only one I know of.

Edited 5/24