The witch's ganglion IS a super rare plant, and yes, Serena knew of it. The fact that it made the professor smile that big and impressed her, brought an actual smile to the redhead's face. Heh.

Wiping the smile off her face, Serena jotted down a few notes and then raised her hand for the next question. "Elladora Ketteridge first discovered the effects of Gillyweed, but a herbologist of the name Beaumont Marjoribanks was later given credit for it." Hmph! If THAT ever happened to Serena...if someone stole her discovery...she'd flick them in the throat.