In the previous mission, The Sadhu, the player located and talked to the Sadhu. Once the player accepts this quest by talking to the Sadhu again, he will ask them to observe the world for one in-game hour. This means about two minutes. After the time has passed, return and talk to him again. This will complete the quest and let the player move on to the next one, Botanical Samples.
The only reward here is the ability to move on to the next quest.
The Sadhu tells the player the following at the Accept/Reject screen.
I was expecting you, <playername>. Villagers visit me to seek advices, and I have been told many times about the stranger without a past that befriends Indian villages and seems at home in this wild world we have all been sent to. You must have been told by some village elder that I would answer your questions. It will not be so easy. My knowledge was great in the old world on the banks of the Holy Ganges, but here I must learn everything anew. If you seek a Guru, you have come in vain.
However... Before I retired to a life of meditation, I was skilled in the knowledge of the natural world. There was not a plant I could not name or use between the Himalayas and the jungles of the south. And while my body has grown frail, my mind is still sharp. Help me study this world and you too will learn much about it. But be warned: not all creatures here are peaceful, and I believe we may face resistance when exploring this world.