Quercus (Oak)

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Quercus L.

Oak

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Rosidae	Roses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more
Order	Fagales	Birch, she-oak, beech, walnut, bayberry, others
Family	Fagaceae	Beech familhy
Genus	Quercus	Latin for “oak”

About plant names...

The genus Quercus, Latin for "oak," includes some 400 species worldwide, of which about 90 are found in North America.

Identification: Most species of oaks can be differentiated by examining leaf shapes, but it isn't easy, since leaf shape in many oaks is extremely variable. Even a single tree can bear a wide range of leaf shapes. Try to assess "average" shape before making a determination based on leaf shape. If acorns are available, their shape is another important identifying characteristic. Many oaks have restricted ranges, another clue.

Following are some species comparisons:

(Quercus) · 5/29/2010 · Nashua River Rail Trail, Pepperell, Massachusetts · ≈ 11 × 7″ (27 × 18 cm) Species not yet identified

	*Quercus agrifolia*	*Quercus alba*	*Quercus bicolor*
Common Name	coast live oak	Eastern white oak	swamp white oak
Plant	These evergreens reach 20-82′ (6-25 m), with trunks up to 4′ (1.2 m) around. Trunks are short and the crowns are wide.	65-80′ (19-24 m) tall, with a wide crown.	65-80′ (19-24 m) tall.
Flowers	Male flowers are catkins 1¾-4″ (5-10 cm) long. Female flowers are ⅛″ (5 mm) long, in clusters of one to three, barely noticeable.
Leaves	Dark green, thick, glossy, oval in shape, alternating, edged with sharp fibers. They are ¾-2½″ (2-7 cm) × ⅜-1½″ (1-4 cm).	Leaves 4-8″ (10-20 cm) long. Leaf tips are rounded.	Leaves are 4-8″ (10-20 cm) long, with many small rounded or slightly sharp lobes.
Stem	Bark is smooth and gray-brown when the tree is young, becoming darker and somewhat furrowed later.
Fruit	Acorns are 1-1½″ (2.5-3.8 cm) long and ⅜-½″ (1-1.5 cm) wide, conical in shape.	Acorns ¾-1″ (1.9-2.5 cm) long. Bumpy cap covers about ¼ of the nut.	Acorns are about 1″ (2.5 cm) long, tan, with one or two on a long stalk.
Range/ Zones
Habitats	Mixed evergreen forests, foothill woodlands, southern oak woodlands
Type	Wild	Wild	Wild
Occurrence	Uncommon	Common	Common

	*Quercus coccinea*	*Quercus ilicifolia*	*Quercus macrocarpa*
Common Name	scarlet oak	bear oak	bur oak
Plant	Typically up to 80′ (24 m) tall, irregular in shape.	A shrub up to 15′ (4.6 m) high.	70-80′ (21-24 m) high.
Leaves	Leaves are deeply lobed, 3-7″ (7.6-17 cm) long, with sharp hairlike tips. Shiny dark green.	Leaves are 2-5″ (5-12 cm) long, shiny and dark green on top, whitish underneath.	About 6″ (13 cm) long, sometimes up to 1′ (38 cm), and very deeply divided. They are yellow-brown in the fall.
Fruit	Acorns ½-1″ (1.3-2.5 cm) long. The cap usually covers half of the nut.	Acorns are ¼-½″ (8.4-12 mm) long, dark brown, with cap covering about ⅓ of the nut.	Large 1-1½″ (2.5-3.8 cm) acorns, half covered by the cap. Cap has a hairy or mossy fringe.
Range/ Zones
Type	Wild	Wild	Wild
Occurrence

	*Quercus rubra*	*Quercus suber*	*Quercus velutina*
Common Name	northern red oak	cork oak	Eastern black oak
Plant	Up to 90′ (27 m) tall.	Up to 66′ (20 m) tall.	65-80′ (19-24 m) tall.
Leaves	5-8″ (12-20 cm) long, with 7-11 lobes and sharp-tipped leaves.	1½-2½″ (3.8-6.3 cm) long, roughly oval, with a few rounded serrations. Drawing by M. Violante.	Leaves are 4-10″ (10-25 cm) long, each with 5-7 lobes. Sun-facing leaves have deeper lobes than shade leaves.
Fruit	Acorns about 1″ (2.5 cm) long, with shallow caps that cover about a fifth of the nut.	Acorns are about 1″ (2.5 cm) long, with large corky caps that cover about half of the nut.	Acorns are ½-¾″ (1.3-1.9 cm) long, with caps that cover ⅓ to ½ of the nut.
Range/ Zones			USDA Zones: 3-9
Type	Wild	Wild	Wild
Occurrence	Common		Common

Online References:

Wikipedia (Quercus)

References:

Sibley, David Allen, The Sibley Guide to Trees, Alfred A. Knopf, 2009, DirrHardyTS

Little, Elbert L., National Audubon Society Field Guide to North American Trees, Eastern Region, Alfred A. Knopf, 1980

(Quercus) · 5/29/2010 · Nashua River Rail Trail, Pepperell, Massachusetts · ≈ 14 × 9″ (35 × 23 cm) Species not yet identified

Oak (Quercus) · 11/11/2008 · Acorn Trail, Great Brook State Park, Carlisle, Massachusetts · ≈ 2½ × 1½′ (84 × 56 cm) Species not yet identified

(Quercus) · 4/23/2010 · Nashua Rail Trail, Ayer, Massachusetts · ≈ 6 × 4″ (15 × 10 cm) Species not yet identified

Quercus description by Thomas H. Kent, last updated 16 Sep 2020.

(Quercus) · 4/27/2010 · Nashua River Rail Trail, Pepperell, Massachusetts · ≈ 4½ × 3″ (11 × 7.9 cm) Species not yet identified

(Quercus) · 1/8/2012 · Groton Place and Sabine Woods, Groton, Massachusetts · ≈ 9 × 6″ (23 × 15 cm) Species not yet identified

(Quercus) · 9/25/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts · ≈ 6 × 9″ (14 × 22 cm) Species not yet identified

(Quercus) · 5/31/2010 · Mt. Lebanon St., Pepperell, Massachusetts · ≈ 9 × 6″ (23 × 15 cm) Species not yet identified

(Quercus) · 9/29/2010 · Nashua River Rail Trail, Ayer, Massachusetts · ≈ 12 × 8″ (31 × 20 cm) Species not yet identified

Range:

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