The buckeye tree Aesculus (Aesculaceae)

The plant is most remarkable for its seed, to which it owes its name in several languages. Native Americans termed it “buckeye” for the resemblance to the eye of a buck, a male deer, a name which settlers translated into English. It is known in French as marron, a word derived from a pre-Roman root marr– with the meaning of “stone, rock” — the seed resembles a large pebble. Marron is both the name of the seed and by derivation that of a shade of brown. The tree is known as the marronnier. The Latin name of the genus, Aesculus, was borrowed from that of an oak tree with edible acorns.

The European species, A. hippocastanum, the horse chestnut, was thus named for the seed resembling a chestnut and for its use once ground up in moderate amounts for feeding horses. It arrived in Western Europe from the Southeastern part of the continent, the Caucasus, the Balkans, the north of Greece and Asia Minor, ca. 1576, and was introduced in France by the Parisian botanist Bachelier ca. 1612.

The 13 main species of the Aesculus genus differentiated from one another much earlier, aeons ago, between 15 and 50 million years. Thus, the European A. hippocastanum and the Californian species A. californica are cousins.

The seeds beg to be collected, they are handsome, smooth and fit perfectly in the hand. They are toxic though. They carry aesculin glycoside, about 10 % per weight, a neurotoxin which also causes hemolysis of red blood cells. Aesculin is nevertheless useful. Microbiologists apply it to a test for identifying bacterial species, especially Enterococci and Listeria.

Native American tribes, the Pomo in Northern California, the Yokuts (also known as Mariposans) in Central California, the Luiseño, or Payomkowishum, in the coastal area of southern California, used the nuts to stun fish in small streams and catch them. American Indians would also grind and soak the seeds in water for several days to leach out the toxin, before using the flour as a foodstuff.