My mother kept a bowl of nuts — with nutcracker — in the living room as both cool-season snack and autumn decoration. Nuts are enough of an autumn symbol that last week I saw a bowl of artificial chestnuts in a gift shop.

Although a lot of plants have seeds large and tasty enough to eat, few are technically “nuts.”

The fruits of seed plants are divided into categories depending on specific characteristics of the fruit. (“Fruits” are what fertilized flowers develop into.)  Both fleshy fruits and dry fruits are further divided, according to which part of the original flower ovary develops into what shape around the seed. As with most seeds, the part animals relish is the cache of food the plant has stored to give its own offspring a good start.

Botanically, a nut is a large, single-seed fruit that doesn’t split open when mature and has a very hard outer shell formed by the ovary wall. Many nuts are also partially covered by a dry or papery husk and a few are completely covered by a dry husk.

Acorns are a classic nut:  a hard shell around the seed with a hard, dry husk forming a cap around it. Oregon has a handful of native oaks, with at least one species representing each of the three major groups of oak — white, red, and live. In general, oaks are grouped by the shape of the leaves and the maturation of the fruit. White oaks have rounded lobes on deciduous leaves and nuts that mature in one year. Red (or black) oaks have pointed lobes on deciduous leaves and nuts that mature in two years — and the nut caps are quite snuggly attached to the seed. Live oaks have toothed, not lobed, leaves that remain on the tree year-round.

Most acorns are bitter enough to require significant blanching or drying before people find them palatable.

Oregon white oak (Quercus garryana) is the stately oak found throughout the Willamette Valley and most of inland Western Oregon. Several red/black oaks or live oaks grow in inland reaches of Southeastern Oregon, notably California black oak (Quercus kelloggii) and canyon live oak (Quercus chrysolepis).

The tanoak (Lithocarpus densiflorus) common in our parts of Southeastern Oregon is in a different genus of the oak family. The sparsely-toothed leaves of tanoak look like live oak leaves with clear valley along the leaf veins; the caps of tanoak’s acorns are armed with spines.

Another member of the oak family found throughout Western Oregon, our local chinquapin (Chrysolepis chrysophylla), has rather long and pointed evergreen leaves and very spiny nut husks.

Closely related to the filbert, Oregon’s native hazelnut (Corylus cornuta) is a nut from the birch family, with a dry, papery sheath tightly wrapped around the hard-shell covered seed.

Many of the edible plant parts we call “nuts” may technically be something else. “Pine nuts” are simply seeds, not nuts. Most botanists categorize walnuts, pecans, almonds, coconuts, and others as dry “drupes” rather than true nuts because of the fleshy or fibrous husk around the hard seed. The “nuts” of Oregon myrtle also are drupes. And, of course, peanuts are not nuts, but legumes (in the pea or bean family) — their pods split to release the seeds within.

Whatever the shape or form the plant ovary takes around the developing seed, the seed’s store of starch and oil can make them favored animal food. That store is often worth the hard work it takes to get through a nut’s protective shell.

I think I’ll put out a bowl of hazelnuts this year.

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For information on how to arrange an exploration of our fascinating natural history for your group or your visiting guests, contact Marty at 267-4027, or e-mail mgiles@wavecrestdiscoveries.com. Questions and comments about local natural history are welcome.