with petiole=___ flat  or  petiole=◯ round :

Petiole=___ flat

blade base=___ flat, ▴▴▴▴ teeth=very small (>5/cm) (>12/in), tree very tall thin
🇪🇺 ◼︎ European black poplar  Populus nigra

blade base=___ flat, ▲▲ teeth=medium (2-3/cm) (5-8/in)
eastern cottonwood  Populus deltoides

blade base= rounded (U-shaped), ▲▲ teeth=few+large, leaf longer than wide
big-toothed aspen  Populus grandidentata

blade base= rounded (U-shaped), ▴▴▴▴ teeth=small, leaf about as long as wide
quaking aspen  Populus tremuloides

Learn more about aspen/​cottonwood/​poplar genus Populus

Part of willow  family Salicaceae.

▭ 🌎︎ Map by county (🇺🇸 USA-48) (colors).

Uses by native peoples
(Ethnobotany database)

Populus hosts caterpillars of 367 species
of butterflies and moths, in some areas.
  This plant is also known to be a host for (in areas where invasive) 🐝︎ spotted lanternfly (SLF)  Lycorma delicatula.

Often grows in clonal colonies [1] —look around for other stems!

🔍︎ 🔍︎ images Discover Life Encyclopedia of Life Michigan Flora Minnesota Wildflowers Flora of North America USDA PLANTS db USFS Wikipedia