Populus is the Latin name for this group of trees. Tremuloides
means tremula-like, because of the resemblance to the European
species of aspen, Populus tremula . Other common names are
trembling aspen and popple. The Lakota know it as canítazipa ,
meaning "bow tree.' ||Aspens belong to the willow family
Salicaceae, along with willow (Salix spp.) and cottonwood
(Populus deltoides ). Aspen leaves are deciduous , alternate,
simple, 1.5 to 3 inches ( 3.8 to 7.6 cm) long, and oval. Each
has fine teeth on the margin. The flowers are in drooping
catkins that are not very showy. The fruit is a 2 to 4-valved
capsule. Aspen twigs are slender, reddish brown with shiny buds.
The bark is smooth and greenish white, but on mature trees the
bark becomes furrowed and dark gray.| Quaking aspen is one of
the most widely distributed trees in North America. It grows
across Canada and the northern United States, from the Atlantic
to the Pacific. Quaking aspen can be found growing as far north
as the Arctic Circle and as far south