Tree seed identification: from acorn, pod or samara to the tree

Acorns and winged seeds

Acorns always mean an oak. The white oak acorn is ovoid to oblong, with a warty, bowl-shaped cap covering a quarter of the nut; it matures in one growing season and the cap always detaches (Virginia Tech). Northern red oak's acorn is 3/4 to 1 inch, nearly round, with a flat, thick cap like a beret, and takes two growing seasons. In summer, a red oak group tree carries two sizes of acorns on its twigs, a white oak only one. The oak page has the full acorn comparison.

Paired samaras are the maples' "helicopters". Sugar maple pairs are horseshoe-shaped, about 1 inch long, brown when mature in fall. Red maple samaras are 1/2 to 3/4 inch with slightly spread wings, ripening in late spring and early summer. Silver maple has the largest samara of any native maple, wings 1 1/2 to 2 1/2 inches. The season helps: a red or silver maple drops its seeds in spring, a sugar maple in fall.

Single samaras belong to several genera. White ash: one wing on a seed with a full, rounded seed cavity, maturing in fall and dispersing over winter. Elms: round, flat, papery wafers, notched at the tip; American elm's ripen in spring. Tree of heaven: twisted samaras 1 to 1 1/2 inches with the seed in the middle, in long hanging clusters. Tulip tree (yellow-poplar): a cone-like cluster of one-winged samaras, about 2 inches, whose base stays on the tree like a wooden flower.

Nuts in husks

Black walnut fruit is round, 2 to 2 1/2 inches across, with a thick green husk that does not split open, around an irregularly furrowed hard nut (Virginia Tech). The USDA Forest Service's Silvics of North America says the nut ripens in September or October and drops shortly after the leaves fall. Butternut's fruit is lemon-shaped, with a sticky husk. The same Forest Service page describes juglone, a substance in walnut leaves, bark, nut husks and roots, reported toxic to some plants (tomatoes especially) by the USDA Forest Service. See the walnut page.

Hickories differ by husk and nut. Shagbark hickory fruit is nearly round, 1 1/2 to 2 inches, with a very thick husk and a distinctly 4-ribbed nut (Virginia Tech). Bitternut hickory's is smaller, about 1 inch, with a thin husk that is 4-winged above the middle, often dusty yellow, and splits partway from the middle to the pointed tip. Pecan's nuts are oblong, 1 1/2 to 2 inches, brown splotched with black, with thin husks. The hickory page compares the hickories by husk and leaflet count.

Other husked nuts: American beech holds two irregularly triangular, shiny brown nuts in a woody husk covered with spines. American chestnut's husk is large, round and very sharply spiny, 2 to 2 1/2 inches, around 2 or 3 nuts. Yellow buckeye has a smooth, leathery husk around 1 to 3 shiny brown seeds with a pale spot; horse chestnut's husk is very spiny. The chestnut vs buckeye page sets the leaves and husks of American chestnut, Chinese chestnut and Ohio buckeye side by side.

Pods, cones, berries, spiky balls and capsules

Pods. Black locust has flat, light brown pods 2 to 4 inches long holding 4 to 8 kidney-shaped seeds. Honeylocust's pods are 6 to 8 inches, flat, red-brown and leathery, drying and twisting. Eastern redbud's are flat, dry and 2 to 4 inches. Kentucky coffeetree's are thick, 3 to 8 inches long and 1 1/2 to 2 inches wide, with dark seeds in a sticky pulp. The locust page separates black locust from honeylocust.

Cones and cone-like fruit. Conifer cones are covered in the conifer guide. Some broadleaf trees make cone-like fruit too: birch's cylindrical, cone-like fruit breaks apart into tiny winged nutlets, and hophornbeam carries hop-like clusters of papery sacs, each around a small nutlet.

Berries, drupes and pomes. Black cherry: round, dark purple to almost black, about 1/3 inch. Flowering dogwood: shiny, oval, red, 1/4 to 1/2 inch, in clusters of 3 to 5. Blackgum: dark purplish blue, about 1/2 inch. Sassafras: dark blue, held upright in a red cup on a red stalk. Hawthorns carry small yellow to red pomes about 1/4 inch across; Callery pear has small, round, brown pomes about 1/2 inch.

Spiky balls. Sweetgum drops woody, spiny "gumballs" 1 to 1 1/2 inches across, each a cluster of capsules that release two seeds apiece (Virginia Tech). Sycamore's ball is a cluster of tiny seeds on a 3- to 6-inch stalk that hangs on through winter. Osage-orange's fruit is far bigger, 4 to 5 inches, with a brain-like surface. The spiky balls guide separates all of them.

Capsules. Northern catalpa's long, stiff "beans", 10 to 18 inches, are capsules full of flat, papery-winged seeds and may stay on the tree over winter. Cottonwoods, aspens and willows release tiny seeds on cotton from small capsules in late spring and summer. Royal paulownia's oval, 1- to 1 1/2-inch capsules hold thousands of tiny seeds.

Where a photo helps with seeds and nuts

A seed on the ground is a good subject for a photo: it stays still and fills the frame. In Tree Identifier, photograph the seed or nut next to a leaf from the same tree if you can find one, since the app identifies from one photo and the leaf adds a second clue. The app returns a common and scientific name with key traits, but no confidence score and no list of look-alikes, so check the answer against the table above and the tree overhead. Use the follow-up chat to ask how that species' fruit differs from a look-alike, never whether it is safe to eat.

For the full field method, see how to identify trees.