WINTER KEY TO THE SPECIES OF AESCULUS

a.Terminal bud about 2/3 inch long; bud-scales covered with a glaucous bloom, not conspicuously resinous; bark broken into thick plates; prickly bur about 1 inch in diameter.A. glabra, p. [199].
aa.Terminal bud 1-1-1/2 inches long; bud-scales conspicuously sticky-resinous, glistening; bark broken into thin plates; prickly bur about 2 inches in diameter.A. hippocastanum, p. [197].

Horse-chestnut

1. Winter twig, × 3/4.

2. Leaf, × 1/6.