Seed/Nut identification

[BobHelm]

I have been out & about in rural & relaxing Issan for a couple of days.
I was introduced to this strange object.

I guess it was about 2 inches from end to end.
Not unsurprisingly, the locals called it buffalo, or ควาย.
That has made it extremely difficult to find out any more about it on the web & I wonder if anyone has any more details about it or a better name so I can do some searching.
When cracked open the centre contains a Brazil Nut sized seed or nut - I have no idea which but it did seem a little like a nut in consistency & taste. It was nothing like as good as a Brazil Nut in taste but still pretty fine compared to some of the other stuff I ate..

I was told that it only grows in large volumes of still water (like a lake) & that is still very popular with the older generation, but that it is not nearly so desirable (except as an oddity) by youngsters.
But, that was only what I gathered & I could have all of that completely wrong!!!

[jackspratt]

Bob's ya' uncle.

https://www.google.com/search?q=Trapa+b ... 8&oe=utf-8

[BobHelm]

Wow, thanks for that Jack.
Looks like all I was told was true.

[parrot]

They're a variety of water chestnut.......floating water chestnut. You see them sold on the side of the road, although not so much nowadays.

[waanjai]

They sell them during the Winter times along the roads that radially leave Udon. 20 Baht for about 10. I like them and heard only the same info as You did.

[parrot]

If for sale on the side of the road, there's usually a sign.......กระจับ grajap.......although, be careful, someone might be selling jock straps on the side of the road.

[Aardvark]

Anti Cancer properties .... good find =D>