Found in late bloom colors, the alternating leaf clusters are sticky when emerging during the bud stage, and have well pronounced veins extending through the blade across the midrib. Petiole are finely haired near pointed apices. Loses its leaves in Autumn, as illustrated in the pic, where many stipules can be seen attached to the twig, and some loose petiole can also be seen.
Black cottonwood -- round leaf stem, small teeth on edge. Bishop Creek, Intake II campground. Trichocarpa = hairy fruited
Populus trichocarpa (black cottonwood; also known as western balsam poplar or California poplar) is a deciduous broadleaf tree species native to western North America. It is used for timber, and is notable as a model organism in plant biology. Its full genome sequence was published in 2006. It is the first tree species to be sequenced.