Red oaks

The red oaks, Quercus subgenus Quercus section Lobatae, are a group of oaks distinguished by their very bitter acorns that mature in 18 months, and have a woolly inside to the acorn shell. The leaves are also commonly characterised by the presence of a small bristle at the tip of the leaf, and also on any lobes on the side of the leaf. They are found in North America, Central America and northernmost South America.

The acorns are nutritious but, unlike the white oaks, are bitter. They serve as an important food for wildlife, but must be boiled repeatedly to get rid of the bitterness (as did Native Americans in order to be used as human food.

Genus Quercus

Subgenus Quercus. Typical oaks. Widespread; acorns not tightly clustered, with scales on acorn cup arranged in spirals.
Section Lobatae (synonym Erythrobalanus). The red oaks. North, Central & South America. Styles long, acorns mature in 18 months, very bitter, inside of acorn shell woolly.
- Quercus agrifolia - California live oak # - western North America
Quercus canbyi - Canby oak # - Mexico
Quercus coccinea - Scarlet oak - eastern North America
Quercus ellipsoidalis - Northern pin oak - eastern North America
Quercus falcata - Spanish oak, aka southern red oak - eastern North America
Quercus humboldtii - South American Oak # - northern South America
Quercus hypoleucoides - Silverleaf oak # - western North America
Quercus imbricaria - Shingle oak - eastern North America
Quercus incana - Bluejack oak - western North America
Quercus kelloggii - California black oak - western North America
Quercus laevis - American turkey oak - eastern North America
Quercus laurifolia - Laurel oak # - eastern North America
Quercus marilandica - Blackjack oak - eastern North America
Quercus nigra - Water oak # - eastern North America
Quercus palustris - Pin oak - eastern North America
Quercus phellos - Willow oak - eastern North America
Quercus polymorpha - Coahuila oak # - Mexico
Quercus rhysophylla - Loquat-leaf oak # - Mexico
Quercus rubra - Northern red oak - eastern North America
Quercus shumardii - Shumard oak - eastern North America
Quercus texana - Nuttall's oak - south central North America
Quercus velutina - Black oak - eastern North America
Quercus wislizenii - Interior live oak # - western North America

Section Quercus (synonym Lepidobalanus). The white oaks. Europe, Asia, north Africa, North America. Styles short; acorns mature in 6 months, sweet or slightly bitter, inside of acorn shell hairless.

Section Mesobalanus. Europe, Asia, north Africa. Styles long; acorns mature in 6 months, bitter, inside of acorn shell hairless (closely related to sect. Quercus and sometimes included in it).

Section Cerris. Europe, Asia, north Africa. Styles long; acorns mature in 18 months, very bitter, inside of acorn shell hairless or slightly hairy.

Section Protobalanus. Southwest USA & northwest Mexico. Styles short, acorns mature in 18 months, very bitter, inside of acorn shell woolly.

Subgenus Cyclobalanopsis. Cluster-acorn oaks. A large group of evergreen oaks in east Asia with clustered acorns and the scales on the acorn cups in distinct concrescent rings (see photo, top right on the Quercus main page); often treated as a separate genus Cyclobalanopsis.

Species with evergreen foliage are tagged #. Evergreen character has evolved on numerous occasions in Quercus, and does not necessarily indicate that the species concerned are closely related.

For the other sections, see List of Quercus species.