Howard came out of his crease to collect a loose puck and passed it toward Smith, who was skating back along the right boards. But the puck bounced off Smith's right calf and into the circle where Florek shot quickly before Howard could get back.
It was Florek's first career playoff goal after he scored one goal in four regular-season games.
Schenn put Philadelphia in front after Game 1 goat Jason Akeson tied it 2-2 earlier in the period. That was enough for the Flyers to snap a nine-game losing streak at Madison Square Garden and send the series to Philadelphia tied at 1.
Game 3 is Tuesday night.
Jakub Voracek brought the Flyers within 2-1 in the first after Martin St. Louis and Benoit Pouliot staked New York to the early two-goal lead. Emery did the rest, looking especially sharp in the second and third periods while subbing for injured No. 1 goalie Steve Mason.
Henrik Lundqvist stopped 21 shots after a 14-save winning effort in the opener. The Rangers had outscored the Flyers 35-10 during the winning streak and allowed two goals or fewer in each game.
Jake Muzzin and Trevor Lewis scored first-period goals before Jonathan Quick allowed seven goals in the final two periods. Los Angeles heads home for Game 3 on Tuesday looking to get back into this series.
The Kings can take comfort in the fact that the home team has won 18 of the previous 19 games between these teams, including nine in the playoffs.