New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Oak tree

The term oak can be used as part of the common name of any of several hundred species of trees and shrubs in the genus Quercus, and some related genera, notably Cyclobalanopsis and Lithocarpus. The genus is native to the northern hemisphere, and includes deciduous and evergreen species extending from cold latitudes to tropical Asia and the Americas.

Oaks have spirally arranged leaves, with a lobed margin in many species; some have serrated leaves or entire leaves with a smooth margin. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6-18 months to mature, depending on species. Oaks are hardwood trees, and the wood is commonly used in furniture and flooring.

Related Stories
 


Plants & Animals News

September 12, 2025

Hidden within Arctic ice, diatoms are proving to be anything but dormant. New Stanford research shows these glass-walled algae glide through frozen channels at record-breaking subzero temperatures, powered by mucus-like ropes and molecular motors. ...
Scientists at Stellenbosch University have uncovered a rare class of plant compounds, flavoalkaloids, in Cannabis leaves for the first time. Using advanced two-dimensional chromatography and mass spectrometry, they identified 79 phenolic compounds ...
Flathead catfish are rapidly reshaping the Susquehanna River’s ecosystem. Once introduced, these voracious predators climbed to the top of the food chain, forcing native fish like channel catfish and bass to shift diets and habitats. Using stable ...
Plants are spreading across the globe faster than ever, largely due to human activity, and new research shows that the very same traits that make plants thrive in their native lands also drive their success abroad. A study of nearly 4,000 European ...
Tiny ocean microbes called Prochlorococcus, once thought to be climate survivors, may struggle as seas warm. These cyanobacteria drive 5% of Earth’s photosynthesis and underpin much of the marine food web. A decade of research shows they thrive ...
Orangutans, humans’ close evolutionary relatives, have developed remarkable strategies to survive in the unpredictable rainforests of Borneo. A Rutgers-led study reveals that these apes balance protein intake and adjust their activity to match ...
Tiny diatoms and their bacterial partners act as nature’s nutrient factories, fueling insects and salmon in California’s Eel River. Their pollution-free process could inspire breakthroughs in sustainable farming and ...
Some animals don’t age at the same pace, and flamingos may hold the key to why. A decades-long study in France reveals that resident flamingos, which stay put, enjoy early-life advantages but pay later with accelerated aging, while migratory ...
Scientists have uncovered a surprising new healing mechanism in injured cells called cathartocytosis, in which cells "vomit" out their internal machinery to revert more quickly to a stem cell-like ...
Yale scientists discovered that cavefish species independently evolved blindness and depigmentation as they adapted to dark cave environments, with some lineages dating back over 11 million years. This new genetic method not only reveals ancient ...
Whale sharks in Indonesia are suffering widespread injuries, with a majority scarred by human activity. Researchers found bagans and boats to be the biggest threats, especially as shark tourism grows. Protecting these gentle giants may be as simple ...
Even sharks’ famous tooth-regrowing ability may not save them from ocean acidification. Researchers found that future acidic waters cause shark teeth to corrode, crack, and weaken, threatening their effectiveness as hunting weapons and ...

Latest Headlines

updated 12:56 pm ET