Black cottonwood is the largest and tallest of
the poplars, growing 2'-3' (or more) in diameter and well over 100'
tall with a broad open crown. The wood of the trunk is somewhat
soft and whitish, aging to gray, and deeply furrowed in older individuals.
The leaves are ovate, sometimes almost triangular, alternate, dark green
above and lighter beneath, finely serrate with rounded teeth. They
are truncate to cordate at the base and acute to tapered at the apex,
and are positioned on rounded petioles that are from 3/4" to 1-1/2"
long. The winter buds are long-pointed and are covered by a resinous
substance, hence the name 'balsamifera.' The flowers appear in
apetalous catkins, staminate and pistillate on separate trees. The
third and fourth pictures show pistillate catkins. The fruit is
a nearly-sessile spheric to conic 2-4-valved capsule that upon opening
releases minute seeds covered with cottony hairs designed for airborne
dispersal. Black cottonwoods are typically found along stream
margins in sandy soils below 6000' in most of California and bloom from
February to April. They can be easily distinguished from our other
common poplar, P. fremontii, which has leaves that are widely
deltoid with roughly scalloped margins, bright green surfaces both above
and below, and flattened petioles.
Click here for Latin name derivations: 1) Populus
Pronunciation: POP-yoo-lus try-ko-KAR-pa.
Click here for Botanical
Formerly Populus balsamifera ssp. trichocarpa.