Oaks comprise one of the largest and most diverse groups of broadleaved trees in the world - with approximately 500 species worldwide and 60 species in North America. Oaks come in all shapes and sizes. Some have huge, wide-spreading crowns while others are small shrubs; some are evergreen while others are deciduous; some grow on very wet sites while others tolerate drought; some have lobed leaves while others are unlobed. Perhaps the three things that all oaks share are acorns, star-shaped piths (the inner core of the twig), and clusters of large buds at the tip of their twigs.
Fortunately for those of us trying to identify them, only 3 Oregon oaks each tree size, but many more are planted in lawns and parks throughout the state. Three additional natives grow only as shrubs, but they are merely varieties of the other species and will not be described here.
: leaves have rounded lobes; acorns have shallow caps.
: small evergreen leaves may have either smooth or spiked edges; acorns have variable caps.
trees by common name trees by scientific name dichotomous key mystery tree
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