Harry had plenty of experience when it came to identifying Lovage.
In the school year when Hogwarts Voice was founded, he had learned much more about Lovage and similar plants from Wizet during the end-of-year exams.
For instance, regarding the plant mentioned in this question, he remembered not only that it was called "Wild Carrot," but also that it had aliases such as "Queen Anne's Lace" and "Bird's Nest Root."
With that thought, he did not hesitate in the slightest and hurriedly wrote down his answer on the exam paper...
The practical exam that afternoon went just as smoothly for Harry as the written exam had that morning.
As the examiner announced the end of the practical exam, he stretched as he left the Great Hall.
Ron quickly threw an arm around his shoulders. "Harry, how did it go?"
Harry let out a long breath. "Nothing too difficult. The whole thing went smoothly."
Of all the O.W.L. subjects, there were three magical disciplines he had been particularly worried about: Potions, Divination, and Transfiguration.
Now that the Potions exam was over, he naturally felt relieved, and even his steps grew much lighter.
"I thought it wasn't difficult either!" Ron grinned. "Though I nearly messed up while brewing the Invigoration Draught!"
"Luckily, I remembered how to fix it!" There was a note of emotion in his voice. "Honestly, Dumbledore's idea to create Hogwarts Voice was brilliant!"
"If it hadn't been for Wizet's magical paper, I would've panicked the moment I saw the potion turn yellowish-brown. I never would've thought to save it with black beetle eyes!"
"I didn't make any mistakes while brewing the potion." Harry recalled. "It was the written exam this morning where there was a question I nearly couldn't answer. Then I remembered Malfoy's magical paper..."
"Malfoy's magical paper?"