Acorns & Chestnuts
"Bacchus and fostering Ceres, powers divine!
Who gave us corn for mast, for water wine."
Dryden's transl. of Virgil, Georgics
We start with Acorns and their near-relatives the Chestnuts, which is pushing things because these are not major commodities. But as you read above, from Georgics, European myth held that, like swine, early humans lived on oak mast (the yearly crop of acorns) until Ceres (one of the gods of agricultural productivity) gifted mankind with wheat, wine, and animal husbandry. Gerard (1597) tells his readers the “oke” is “astringent, and used … for dysenteries and fluxes of the blood,” and the acorns “yield no nourishment to man’s body except that which is grosse, raw, and cold.” As livestock feed however, “swine are fatted herewith and by feeding on them have their flesh hard and sound.” In antiquity, therefore, Europeans relegated acorns to husbandry and medicinal use. For other creatures, acorns absolutely prove to be a major food source, the annual production (the mast) being a solid indicator of the year ahead for wild animals.
Across the Atlantic, in the “New Found World”, although they had corn, indigenous American cultures persisted in using acorns as an important food source, even into traditions of today. [https://www.archives.gov/education/lessons/acorn]
Because the seed are rife with tannins and other bitter compounds, people developed techniques for extensive leeching and cooking to make them palatable and digestible. It’s possible acorns show up in markets somewhere, but that would be a curious specialty. Acorns are uncommon fare.
If they were to be offered at a market, Acorns would certainly be found with Nuts, which many morphologists regard as an imprecise catch-all for any hard, dry, indehiscent (not opening at maturity), one-seeded fruit (yes, fruit), such as Chestnuts, Walnuts, and Pecans. We learn that the carpologist sees things from the viewpoint of the final product, not how it grew. Acorns (Quercus) have cupulas while Chestnuts (Castanea) are enclosed, completely wrapped in a calybium.
Acorns are unique to oaks (Quercus), which to the Carpologist is a kind of fruit called a Glans.
So Chestnuts are more cryptic. Whereas an acorn is a single pistil of an individual female flower, with a basal cap, the sea urchin-like spiny structure made by chestnuts completely surrounds several flowers (typically 3.) When you break open a spiny chestnut, it is pretty much equivalent to finding that an over-enthusiastic cap harbors several acorns. [see http://patacf.org/wp-content/uploads/2014/04/flower-to-chestnut.pdf] But this sets off the Carpologist, who regards chestnuts as radically different from acorns. Dr. Spjut calls the chestnut fruiting structure a Trymosum, and goes as far as considering Chestnut pistils as “inferior,” as being buried down in stem structures.
To Systematists, there isn’t a huge difference between Quercus and Castanea. Systematists would group acorns with chestnuts and beechnuts, and in the same order as hazelnuts, because these fruit are produced by the related genera Quercus, Fagus, and Castanea (in the Fagaceae) and Corylus (in the Betulaceae). The Oak simplifies female flowers as individual productions, a near-naked pistil covered somewhat by a cup made of stem and scale leaves (the reduced residuum of a much more complex ancestral inflorescence), while Chestnut has a few tightly clustered female flowers that develop tucked deeply into the cup (excuse me, the calybium); in each case there isn’t much else to a female flower than a pistil. It just isn’t a big deal.
And none of this is of importance to the Cook, who is concerned mainly with the fleshy, somewhat mealy kernel (the seed) inside; the prickly or scaly structure is useful only for presentation or decoration. Chestnuts have long been consumed in China, Europe, and America. Gerard comments: “Of all the Acorns, saith Galen, the Chestnuts are the chiefest, and do only, of all the wild fruits, yield to the body commendable nourishment.” So the Cook might look for chestnuts to roast on an open fire, finding these “nuts,” each of which is a one-seeded fruit made by a single flower that once lived in a testy and decorative burr with one or two compatriots. As for acorns, slim chance you’ll see these fruit for sale in a market.
Beechnuts are structured like Chestnuts, and considered the same kind of fruiting structure by the morphologist. Their fruit are produced, usually, as a pair of hard, one-seeded pistils, wrapped up in a 4-lobed spiny (muricate) envelope (an involucre). Each of the paired beechnuts was made by a different flower. Looking at Quercus, Castanea, and Fagus and disregarding the precise nature of the enwrapping structures, we see great similarity. They are all deciduous woody plants that produce tassels of male flowers, a useful strategy for wind-pollinated trees. And each forms female flowers wrapped in some kind of scaly or spiny covering.
The creation of a thousand forests is in one acorn.
Ralph Waldo Emerson, 1841
Beechnuts: nice images are found at: http://rawedibleplants.blogspot.com/2014/09/beech-nuts-fagus-sylvatica.html
https://www.jstor.org/stable/pdf/2429268.pdf?refreqid=excelsior%3A019ec7723c2603a676424500cc9e127f D. W. Brett, 1964. “The Inflorescence of Fagus and Castanea, and the Evolution of the Cupules of the Fagaceae”, The New Phytologist 63(1):96-118.