Rolfe tells you that dancing is a greeting among sylphs, and he has more insights to share.
This quest is available if you have completed the quest Sylphic Studies.
Starting the Quest
Talk to Rolfe Hawthorne in the Hawthorne Hut in the East Shroud to start the quest.
Speak with Rosa
Go out by the west exit of the Hawthorne Hut and make your way northwest to the Fullflower Comb and talk to Rosa.
Use the Amber Syrup on the Curious Tussock
Go east and use the amber syrup on the Curious Tussock. An Ochu will attack. When you kill it, you will get milkroot.
Present the Milkroot to Rolfe Hawthorne
Go back into the Hawthorne Hut and talk to Rolfe to hand over the milkroot.
Next Main Scenario Quest
After completing the quest, you will need to be at least level 21 to proceed to the next quest. After you reach level 21, talk to Rolfe to accept the next quest: First Contact. There will be a cutscene.