The flower you were suppose to be looking for was called Moonglow, because at night it would glow under direct moonlight. Obviously being that it's still the middle of the day, the flowers would not bloom making it much harder for you or Pylia to find the flowers. Worse part was that without the moon the flowers didn't look too much different from the various spiky grasses and weeds that dotted the beach, and Moonglow had to be handled carefully. After about an hour of searching, neither of you had much luck finding moonglow. The sun was starting to set with a red horizon in the distance. "Red sunset means it's going to rain. Hopefully it'll only be tonight and not tomorrow." Pylia says as she points towards the horizon. 

There was still about two hours before sunset, so if you'd like you could try and stay out here a bit longer. Pylia thinks maybe they'll have better luck this time. Alternatively, you could leave the herb hunt to her since she knows what she's looking for, and you can try and look for other things on the beach. Finally you could always return back to Cassari. You have some tools now, which you could either refurbish or sell to those traders. There didn't seem to be anything particularly dangerous on the beach though occasionally you'd see the outlines of a goblin wandering the beach, but they never seem to head in your direction.