Contains 41 accepted taxa overall.
Characteristics
Classification
Citation
QUERCUS Linnaeus, Sp. Pl. 994. 1753.
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TYPE: Quercus robur Linnaeus 1753. Lectotypified by Britton & A. Brown, Ill. Fl. N. U.S., ed. 2. 1: 161. 1913.
Species
| Scientific Name | Common Name | Herbarium Specimens | Status | Photos |
|---|---|---|---|---|
| Quercus alba | WHITE OAK | Native FACU (NWPL) | ||
| Quercus arkansana | ARKANSAS OAK | Native Threatened-State | ||
| Quercus austrina | BASTARD WHITE OAK | Native | ||
| Quercus chapmanii | CHAPMAN'S OAK | Native | ||
| Quercus falcata | SPANISH OAK; SOUTHERN RED OAK | Native FACU (NWPL) | ||
| Quercus geminata | SAND LIVE OAK | Native | ||
| Quercus incana | BLUEJACK OAK | Native | ||
| Quercus inopina | SCRUB OAK | Native | ||
| Quercus laevis | TURKEY OAK | Native | ||
| Quercus laurifolia | LAUREL OAK; DIAMOND OAK; DARLINGTON OAK | Native FACW (NWPL) T (WAP) FACW (DEP) | ||
| Quercus lyrata | OVERCUP OAK | Native OBL (NWPL) OBL (DEP) | ||
| Quercus margarettae | SAND POST OAK | Native | ||
| Quercus marilandica | BLACKJACK OAK | Native | ||
| Quercus michauxii | BASKET OAK; SWAMP CHESTNUT OAK | Native FACW (NWPL) FACW (DEP) | ||
| Quercus minima | DWARF LIVE OAK | Native FAC (NWPL) | ||
| Quercus muehlenbergii | CHINKAPIN OAK | Native UPL (NWPL) | ||
| Quercus myrtifolia | MYRTLE OAK | Native | ||
| Quercus nigra | WATER OAK | Native FAC (NWPL) T (WAP) FACW (DEP) | ||
| Quercus pagoda | CHERRYBARK OAK | Native FACW (NWPL) FACW (DEP) | ||
| Quercus phellos | WILLOW OAK | Native FACW (NWPL) FACW (DEP) | ||
| Quercus prinoides | DWARF CHINQUAPIN OAK | Native | ||
| Quercus pumila | RUNNING OAK | Native | ||
| Quercus shumardii | SHUMARD'S OAK | Native FAC (NWPL) | ||
| Quercus stellata | POST OAK | Native UPL (NWPL) | ||
| Quercus velutina | BLACK OAK | Native | ||
| Quercus virginiana | LIVE OAK | Native FACU (NWPL) U (WAP) | ||
| Quercus x ashei | Native | |||
| Quercus x atlantica | Native | |||
| Quercus x beadlei | Native FACW (NWPL) | |||
| Quercus x caduca | Native | |||
| Quercus x comptoniae | Native | |||
| Quercus x harbisonii | Native | |||
| Quercus x mellichampii | Native UPL (NWPL) | |||
| Quercus x neopalmeri | Native | |||
| Quercus x oviedoensis | Native | |||
| Quercus x rolfsii | Native | |||
| Quercus x rudkinii | Native | |||
| Quercus x subintegra | Native | |||
| Quercus x succulenta | Native | |||
| Quercus x venulosa | Native | |||
| Quercus x walteriana | Native |
Identification Key
1. Mature buds somewhat conic and acute towards the tip; trichomes absent, simple, fasciculate (arms generally spreading or ascending from a central base, the base sometimes stipe-like), or stellate (arms generally horizontal and fused at a central point); leaf blades sometimes with a bristle or awn at the leaf tip or lobe tips; acorn cup scales flattened; acorns usually more bitter or astringent, maturing in the second year; bark of larger trees often with smoothish ridges only shallowly fissured, some species having blocky bark; section Lobatae (red oaks)
1. Mature buds somewhat globose-ellipsoid and rounded at the tip, or if conic and acute towards the tip then the leaf blades with numerous nearly straight and parallel secondary veins; trichomes absent, simple, fasciculate (arms generally spreading or ascending from a central base, the base sometimes stipe-like), or multi-radiate (arms generally spreading or ascending, arising from 2 or more points or bases, sometimes rosulate); leaf blades without bristles or awns, sometimes with a short mucro; acorn cup scales thickened, tuberculate; acorns usually sweeter, maturing in one year; bark of larger trees often platy, blocky, strongly ridged, or strongly fissured; sections Quercus and Virentes (white oaks)
1. (Key A) Leaf blades mostly deeply lobed, the sinuses ⅓ or more as long as the distance from the midrib to the leaf blade margin
2
1. Leaf blades mostly entire to shallowly lobed, the sinuses ⅓ or less as long as the distance from the midrib to the leaf blade margin
6
2. Lower surface of the mature leaf blade tomentose with yellowish gray trichomes
3
2. Lower surface of the mature leaf blade glabrous to glabrate except for tufts of trichomes in the vein axils
4
3. Bark with rough ridges; base of leaf blade typically U-shaped; leaf blade lobes 3-7
3. Bark with somewhat lustrous and platy or smooth ridges; base of leaf blade typically angular; leaf blade lobes typically 5-11
4. Petiole 0-13 mm long; leaf blade base acute at a narrow V-shaped angle; young leaf blade often orange scurfy
4. Petiole 13-70 mm long; leaf blade base truncate to broadly angular; young leaf blade pubescent or glabrous
5
5. Buds glabrous or pubescent only at the tip; acorn cup covering ⅓ or less of the nut
5. Buds pubescent in distal half; acorn cup covering ½ or more of the nut
6. Leaf blades broader towards the apex and much narrower towards the base, often somewhat lobed with the margins not evenly rounded nor straight on some parts
7
6. Leaf blades mostly elliptic to obovate (at least in outline), not much broader towards the apex and not much narrower towards the base or only slightly so, generally without lobes, the margin mostly evenly rounded to straight
9
7. Leaf blades usually pubescent on the lower surface
7. Leaf blades glabrous to glabrate on the lower surface, or only pubescent in the vein axils
8
8. Leaf blade about as wide as long, or slightly longer than wide
8. Leaf blades 1.5-2.5 times longer than wide
9. Mature leaf blades finely and densely tomentose on the lower surface
10
9. Mature leaf blades glabrous to pubescent with scattered, spaced hairs, only densely pubescent in the vein axils on the lower surface or only densely pubescent with reddish hairs on young blades
11
10. Trees, usually more than 2 m tall when mature; rays of stellate hairs to 0.3 mm long on stems; leaf blade apex rounded
10. Shrubs, usually less than 2 m tall when mature; rays of stellate hairs to 0.7 mm long on stems; leaf blade apex acute
11. Leaf blades about 1-2 times as long as wide, revolute at least on the margins
12
11. Leaf blades about 2-7 times as long as wide, not conspicuously revolute
13
12. Leaf blades strongly revolute, often with yellow to reddish scurfy pubescence, elliptic to broadly elliptic, ca. 2 times longer than broad
12. Leaf blades finely revolute only on the margins, usually without yellow to reddish pubescence, obovate to broadly elliptic, often less than 2 times longer than broad
13. Leaf blades 3.5-7 times as long as wide
13. Leaf blades 2-4 times as long as wide
14
14. Twigs often grayish; leaves essentially evergreen, blades 3.5-5.5 cm long, 0.7-1.6 cm wide, the base obtuse to rounded with the basal angle 94-244 degrees, the apex acute to acuminate with the apical angle 49-153 degrees, coriaceous, lustrous, often dentate, slightly revolute, opaque, essentially glabrous, venation more prominent on the upper surface, petiole 0.7-1.8 mm, twigs grayish; mostly of drier sites
14. Twigs often reddish; leaves tardily deciduous, blades 6.5-8.8 cm long, 1.8-2.6 cm wide, the base attenuate to cuneate with the basal angle 20-130 degrees, the apex obtuse to rounded with the apical angle 144-213 degrees, moderately coriaceous, moderately lustrous, never dentate, not revolute, translucent, venation more prominent on the lower surface, twigs reddish tinted; mostly of wetter site
1. (Key B) Leaf blades mostly deeply lobed, the sinuses ⅓ or more as long as the distance from the midrib to the leaf blade margin
2
1. Leaf blades mostly entire to shallowly lobed, the sinuses ⅓ or less as long as the distance from the midrib to the leaf blade margin
6
2. Leaf blades glabrous and whitish on the lower surface
2. Leaf blades pubescent on the lower surface (at least in the veins axils) and not whitish
3
3. Lobes of leaf blades mostly acute and mucronate
3. Lobes of leaf blades mostly rounded, scarcely or not mucronate
4
4. Mature leaf blades glabrous to glabrate on the lower surface
4. Mature leaf blades densely to sparsely pubescent on the lower surface
5
5. Young twigs glabrous to sparsely pubescent; larger leaf blades mostly 9 cm long or less, the stellate hairs of the lower surface with 2-6 rays
5. Young twigs densely pubescent; larger leaf blades mostly 10 cm long or more, the stellate hairs of the lower surface with 6-10 rays
6. Leaf blades with 10 or more teeth or shallow lobes at the terminus of nearly straight secondary veins along each side
7
6. Leaf blades entire or with few lobes, the secondary veins irregular and branching
9
7. Shrubs, usually less than 5 m tall when mature; leaf blades mostly with 3-8 secondary veins on each side of the midrib
7. Trees, taller than 5 m when mature; leaf blades with 8-20 secondary veins on each side of the midrib
8
8. Larger leaf blades 12-28 cm long, the teeth usually rounded, secondary veins 15-20 on each side, with 1-4-rayed stellate hairs on the lower surface; nut 2.5-3.5 cm long
8. Larger leaf blades 10-18 cm long, the teeth mostly acute, secondary veins 9-15 on each side, with 6-10-rayed stellate hairs on the lower surface; nut 1.5-2.3 cm long
9. Mature leaf blades pubescent on the lower surface with yellow to reddish hairs and only sparsely stellate, the blade shape somewhat obovate, broader towards the apex to faintly 3-lobed at the apex
9. Mature leaf blades densely tomentose with stellate hairs on the lower surface, the blade shape mostly elliptic, sometimes slightly broader towards the apex, sometimes shallowly lobed along the margin (section Virentes)
10
10. Shrubs, usually 1.5 m tall or less when mature
10. Trees, usually 3 m tall or more when mature
11
11. Leaf blade margins strongly revolute; secondary veins impressed on the upper leaf blade surface; many rays of the stellate hairs spreading to ascending above the surface and not appressed, only some stellate hairs appressed
11. Leaf blade margins flat to slightly revolute; secondary veins flat to inconspicuously impressed on the upper leaf blade surface; all rays of the stellate hairs closely appressed to the lower leaf blade surface
Genus Synonyms
| Synonym | Full Citation | Basionym | Type |
|---|---|---|---|
| Balanaulax | Balanaulax Rafinesque, Alsogr. Amer. 28. 1838. | TYPE: Balanaulax molucca (Linnaeus) Rafinesque 1838. (Quercus molucca Linnaeus 1753.) | |
| Cerris | Cerris Rafinesque, Alsogr. Amer. 29. 1838. | TYPE: Non designatus. | |
| Cyclobalanopsis | Cyclobalanopsis Oersted, Vidensk. Meddel. Dansk Naturhist. Foren. Kjoebenhavn 1866: 77. 1867, nom. cons. vs. Perytis Rafinesque 1838. (= Quercus Linnaeus) | TYPE: Cyclobalanopsis velutina Oersted 1867. (Quercus velutina Lindley ex Wallich 1831, non Lamarck 1785.) | |
| Dryopsila | Dryopsila Rafinesque, Alsogr. Amer. 25. 1838. | TYPE: Non designatus. | |
| Eriodrys | Eriodrys Rafinesque, Alsogr. Amer. 30. 1838. | TYPE: Eriodrys lanata (Smith) Rafinesque 1838. (Quercus lanata Smith 1819.) | |
| Erythrobalanus | Erythrobalanus (Oersted) O. Schwarz, Notizbl. Bot. Gart. Berlin-Dahlem 13: 8. 1936. | BASIONYM: Quercus Linnaeus, subg. Erythrobalanus Oersted, Vidensk. Meddel. Dansk Naturhist. Foren. Kjoebenhavn 1866: 65. 1867. | TYPE: Non designatus. |
| Perytis | Perytis Rafinesque, Alsogr. Amer. 29. 1838, nom. rej. vs. Cyclobalanopsis Oersted 1867. | TYPE: Perytis lamellosa (Smith) Rafinesque 1838. (Quercus lamellosa Smith 1819.) Lectotypified by Pichi-Sermolli, Taxon 3: 114. 1954. | |
| Scolodrys | Scolodrys Rafinesque, Alsogr. Amer. 29. 1838. | TYPE: Non designatus. | |
| Suber | Suber Miller, Gard. Dict. Abr., ed. 4. 1754. | TYPE: Quercus suber Linnaeus 1753. |