All species look alike microscopically.
The word populus is the classical Latin name for the poplar tree. The wood is weak in bending and compression, soft and low in shock resistance. It has a sour odor when wet, but no characteristic odor or taste when dry. Tension wood is frequently present, causing a fuzzy surface when cut. Cottonwood glues well, has low nail-holding ability, does not split easily, and holds paint well.