How to identify the different species of Quercus - Oaks
- Joana Alves Gomes
- Sep 30
- 2 min read
Oak trees are among the most beloved species of Portuguese flora, belonging to the Quercus genus and the Fagacea family.
There are certain characteristics that allow us to identify the Quercus genus and others that allow us to distinguish the various species—let's explore the topic!
All Quercus species are characterized by a type of fruit called an acorn, pendulous catkin inflorescences, often rounded or toothed leaves, less frequently entire, a thick trunk, and gray-brown bark with deep longitudinal grooves.
Taxonomic Classification:
Genus: Quercus
Family: Fagaceae
Order: Fagales
Subclass: Hamamelididae
Class: Magnoliopsida
Subdivision: Magnoliophytina (Angiospermae)
Division: Spermatophyta
How can you distinguish between the different Quercus species?
By observing the trunk and the shape of the leaves and fruit.
- Quercus canariensis, Algerian Oak
A species native to the Serra de Monchique, with other specimens found in parks and gardens throughout the rest of the country. Oak with dark green leaves, up to 18 cm long, and a crenate margin.
- Quercus coccifera, Palestine oak
A wild-growing species in Portugal, distributed primarily in central and southern Portugal, on slopes and mountain peaks.
Usually a shrub up to 2 m tall, it has oblong to elliptical, toothed leaves, dark green on the upper surface and yellowish-green on the underside.
The acorns are 1.5 to 2.5 cm in size, enclosed in a dome with scales, and mature only in the second year.
- Quercus coccinea, American red oak
A species of leaves similar to Quercus rubra; however, these are brighter, more deeply divided and the central pair of lobes is larger than the others.
- Quercus faginea, Portuguese oak/cerquinho
Spontaneous species in Portugal, distributed mainly on the slopes and peaks of central and southern Portugal and the Douro region.
- Quercus pyrenaica, Pyrenean oak
A wild species in Portugal, distributed primarily in the northern interior, central, and occasionally southern Portugal, on mountain peaks, slopes, and plateaus.
Its foliage is easily distinguished by its velvety underside, a characteristic due to the presence of soft filaments that are noticeable to the touch.
- Quercus rubra, American oak
Leaves divided almost to the center of the leaf into about 7 to 11 pairs of triangular, pointed lobes, each with 1 to 3 sharp teeth.
The acorn is rounded, about 2.5 cm long, has a short stalk, and sits on very flat cupules, maturing only in the second year.
- Quercus robur, Common oak
A wild species in Portugal, distributed primarily in the north.
Asymmetrically shaped, lobed leaves with a short stalk, dark green on the upper surface and light green on the underside. The acorns are long, about 3/4 cm, with long petioles measuring 2 to 8 cm, and cupped with flat scales.
- Quercus suber, Cork oak
The tree's crown is dense, and its trunk is easily recognizable by its cork covering. The leaves are oval, oval-lanceolate, and denticulated, dark green above, gray and pubescent below. The fruit is reddish-brown and ripens annually.
Which one is your favorite? Leave a comment!
To learn more about the different species of Acer, read this article:
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