with leaf scars=:
narrow raised;  terminal buds=hairy;  buds have hairy inner-scale between 2 outer-scales  or
crescent-shaped, with 3 bundle scars, centered above is side bud scale :

Leaf scars=narrow raised;  terminal buds=​hairy;  buds have hairy inner-scale between 2 outer-scales

twigs=smooth;  outer bud scales=sticky
🗻︎ American mountain ash  Sorbus americana
twigs=hairy
🇪🇺 🗻︎ European mountain ash  Sorbus aucuparia

Leaf scars=crescent-shaped, with 3 bundle scars, centered above is side bud scale

terminal buds       > 25 mm (>1 in)  or
terminal buds about 12 mm (½ in) :

terminal buds       >25 mm (>1 in)

fragrant, lots of resin, twigs=red-brown
balsam poplar  Populus balsamifera  or
balm of Gilead  Populus × jackii

terminal buds about 12 mm (½ in)

terminal buds egg-shaped;  twigs=gray-to-brown
♒︎ swamp cottonwood  Populus heterophylla
terminal buds ♦ taper at both ends;  twigs=​yellow-to-yellow-brown
eastern cottonwood  Populus deltoides

Navigate to pages that link here

🏠︎ 🌳︎🍃︎ broadleaf branches, ╟ alternate, list of attributes, no catkins thorns pods, w/terminal buds