Once you have defeated the Flowering Cactoid hunt you will have access to a new side quest which will let you gain access to the Barheim Key (vital for obtaining all the espers and some other hidden gems).

This part is available for when you escape from the Barheim Passage. Once you have claimed your reward for the hunt talk to Dantro again where he will ask for you to take the flower to his wife at the South Bank Village (just head as far north as you can in the Eastersand). There's a gandy Gate Crystal here, so be sure to use it for easy access later on. Talk to the Villager by the hut - Dantro's wife. She's looking after an injured traveller and needs a special type of medicine. Give her the Cactus Flower and she'll reward you with a Bunch of Needles for your assistance. Talk to her again and she'll explain that she needs some Semclan Shells to ease the patient's pain. Go wade in the shallow water along the shoreline, where you will see tiny objects glistening in the sun; when you approach one it will be identified as a "Mysterious Glint". Pick up at least one and take it back to Dantro's Wife. If, however you want the best reward, you'll need to pick up all five Semclam Shells. You can find one in the Village shoreline and the other three outisde the Village in the Banks of Nerbra shoreline.

After receiving the Semclam Shells, Dantro's Wide will tell you that also needs some Nebralim to stem the patient's bleeding. Head back to the Outpost and speak to Dantro again. Take a Phial of Nebralim (but ideally two for best reward) from the nearby crates. Return to the South Bank Village and give the Nerbralim to Dantro's Wife. She now needs some Valeblossom Dew to neutralise the poison. However this is in the Broken Sands so you will need to carry on with the storyline for a bit.

In between these two parts, there is a hunt in Bhujerba called The Hunt for the Nidhogg. Here you receive a Great Serpentskin. Do not sell this as you need it to receive the best reward.

When you have finished the Tomb of Raithwall and Shiva part of the storyline and completed the side quest, The Case of the Missing Cactoid, you can now continue with this side quest.

Head over to the North Bank Village to reach the Yoma. Be careful as you travel through this area as the Worgen are quite powerful; you should also avoid traps and the Wild Saurian which will attack you. Head north to enter the Broken Sands and look for the trees that have purple like leaves (it will also say "Mysterious Glint" if you are by the correct parts). Examine the tree to obtain a Drop of Valeblossom Dew. You can collect up to three so to get the best reward find three of them.

Once you have all three return back to the South Bank Village and give the Valeblossom Dew to Dantro's Wife, if you have kept the Great Serpentskin then she will spot it and ask for it so give it to her.

Now exit the village and do a couple of battles to make sure the patient recovers, then return to the Village and talk to Dantro's Wife for the final time. She will tell you that the patient has fully recovered and is waiting at the back of her hut to speak to you.

THE REWARD

The final gift that you receive from the traveller depends on thier race (if you followed the above exactly you should have the Moogle):

Race	Reward
Bangaa	Barheim Key, Balance Mote
Hume	Barheim Key, Magick Gloves
Moogle	Barheim Key, Golden Amulet