Opposite Twig Configurations of Trees in Canada

These Canadian species have opposite twig configuration (as seen in thumbnail). One (1) asterisk means the tree is introduced (not native). Two (2) asterisks means the tree is not native but is naturalized (reproducing itself). "(Genus)" means the hint refers to a genus of opposite-twig trees, while "(species)" means the hint refers to a tree that is unique from the rest of its genus/family. Latin names (G+s), common names, and alternative names will be accepted.