The Chestnut Oaks, Quercus montana, are ripening in Prospect park. This species’ common name stems from the leaves, which are somewhat chestnut-like, although the acorn, over an inch long in this species, is all oak.The remains of a squirrel feast on what I believe is Yellow Buckeye, Aesculus flava, in the Vale. Included here because it’s related to the Common Horsechestnut, Aesculus hippocastanum: the shiny brown nuts or conkers of both are quite similar. Buckeyes are native to North America and are distinguished from the Eurasian horsechestnut — which is now widely cultivated here, and the species you are more likely to run into in the city — by having five leaflets instead of the horsechestnut’s seven.At last, actual chestnuts! This is some kind of cultivar of European or Sweet Chestnut, Castanea sativa, source of the chestnuts you roast on the open fire. I’m cheating a little here because this isn’t in Prospect Park, it’s on Chestnut Street on Nantucket. But for instructional purposes, note how the spiny husk is quite similar to American Chestnut, a few of which grow in Prospect.
So whence this confusing multi-use name “chestnut”? It goes back to the Old English chesten, the name for the sweet chestnut of Eurasia, the C. sativa of above. Chesten has a Greek source, the name for the nut of either Pontus, on the Black Sea, or Thessaly, which would be the same nut, methinks.
A special note for pot-heads: “sativa” is used in many botanical names, and is derived from the Latin verb for to sow.