Yellow buckeye (Aesculus flava)
North edge of Old Main
This close relative of our common horse chestnut (Aesculus hippocastanum) can be distinguished by its smaller leaves and upright habit; tall, with drooping lower branches. Its flowers resemble those of the horse chestnut, but are yellow. Its fall colors are superior. Experts suggest that the yellow buckeye is less commonly planted than Aesculus hippocastanum because it is less tolerant of the environmental stresses of urban life. However, this particular yellow buckeye seems to be thriving as a canopy protecting the plaza where much of Old Main comes to smoke!
Yellow buckeye also is known as sweet buckeye, for reasons that are not at all obvious. The nut-like fruit of Aesculus flava is said to have been extensively processed and ultimately eaten by Native Americans. Apparently it was reduced to a much-leached gruel-like substance, probably devoid of much nutritional value. Whether or not the gruel was sweet is difficult to determine; language used by several experts suggests that no one has eaten it in living memory. Yellow buckeye nuts contain a chemical (satonin) that is useful in making detergents, but is mildly toxic to humans. Leave the nuts to the squirrels.
The yellow buckeye is native to eastern and southeastern United States, where it can approach 150 ft. in height and 6 ft. in diameter.
See Aesculus flava on Wikipedia.