Populus is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (//), aspen, and cottonwood.
In the September 2006 issue of Science, it was announced that the Western Balsam Poplar (P. trichocarpa) was the first tree to have its full DNA code sequenced.
Yosemite Valley (pron.: // yoh-SEM-i-tee) is a glacial valley in Yosemite National Park in the western Sierra Nevada mountains of California, carved out by the Merced River. The valley is about 8 miles (13 km) long and up to a mile deep, surrounded by high granite summits such as Half Dome and El Capitan, and densely forested with pines. A multitude of streams including Tenaya, Illilouette and Bridalveil Creeks join in the valley, and flow out of the valley's mouth as the Merced River, which eventually flows to the Pacific Ocean. The valley is renowned for its natural beauty, and is widely regarded as the centerpiece of Yosemite National Park, attracting visitors from around the world.