"There grew a little flower 'neath a great oak tree," (Runaround.119) is a line from Ruddigore, a Gilbert and Sullivan operetta. Gilbert and Sullivan get mentioned again (120, 214, and Catch that Rabbit.16) but the important thing to note is that they wrote a lot of funny operettas in their day. And Speedy seems to know them all.
"Lover's professions when uttered in Hessians" (Runaround.189) is a line from Patience, a Gilbert and Sullivan operetta.
"When you're lying awake with a dismal headache and repose is tabooed—" (Runaround.221) is a line from Iolanthe, another Gilbert and Sullivan operetta.