In Luang Prabang, Laos, I was served this mystery herb on the side of a dish of green papaya salad (ຕຳຫມາກຫຸ່ງ tam mak hung, aka som tam on the Thai side of the border).

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What exactly is this? The flavor was quite strong and rather bitter. Google Lens thinks it's either khat or asparagus, both of which are quite definitely wrong.

  • Leaves bring to mind legumes to me, but hard to say without an opened out version. Might also get a better answer if migrated to Biology SE.
    – bob1
    Oct 27, 2022 at 1:08
  • Looks a bit like chamberbitter, but I'd be surprised if that's really what it is as it's somewhat toxic.
    – barbecue
    Oct 28, 2022 at 23:46
  • @bob1 looks like it is indeed a legume (at least according to Wikipedia).
    – Esther
    Nov 2, 2022 at 16:15

1 Answer 1


I think that is Neptunia oleracea (Water Mimosa).

The leaves are normally fanned out but collapse in when touched.

It is a vegetable "commonly eaten raw or stir-fried in Thailand" https://www.tarladalal.com/glossary-water-mimosa-1481i

You can see the leaves aligning more here: https://www.gbif.org/occurrence/3334636150

Apparently the roots are also used medicinally in Malaysia and Thailand for things such as headaches, earaches, and skin wounds. https://pondinformer.com/water-mimosa-neptunia-oleracea/

  • 2
    canstockphoto.com/water-mimosa-36364232.html supposedly a stock photo of water mimosa in a salad. It looks exactly like the original photo except for the color. Nice find!
    – Esther
    Nov 1, 2022 at 17:08
  • 1
    Bingo, I think you've found it! The Lao name is the same as Thai: ຜັກກະເສດ phak kachet. Nov 2, 2022 at 0:28
  • 2
    Good answer. I knew I had seen leaves looking like that before, but was failing to bring to mind where/when - it was on Mimosa pudica ("sensitive plant") after touching the leaves and seeing them collapse, results in almost exactly the same pattern and coiled shape.
    – bob1
    Nov 2, 2022 at 20:45

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