dear Anne- no the Areca nuts are rounded shapes- the Trapa Natans or Caltrop is a hard black seed pod with spikey bits, -hard to show without cutting the string... the name water chestnut is totally misleading. you will see lots of images of you google it... i'm still having problems sending images...

sorry if i misunderstood your comment - i think you are perfectly right about the round fat mottled nut next to the Caltrop pod with 4 horns!

this necklace includes 4 examples of Thevetia peruviana =yellow Oleander--the pods which are shaped a bit like a bulging handbag- but beware the plant is poisonous.

These mala’s with Bodhi beads are modern Chinese mass production, but interesting.
There are always 18 beads + Guru bead, and as far as I know every individual bead represent an Arhat or wise man. I make a sport out of it to find out the botanical and Chinese name of each bead. Impossible! There are too many variations of the way the seeds are processed. Also a lot of seeds are given just commercial names that varies by each commercial dealer. The seeds used here, are imported from all over the world to China I presume. Moreover, the mala's and other organical beads are nice to collect.
Hereby a Chinese mala with Trapa bicornis and one single Trapa natans.
The big acorn like, top right, in Stefany's picture is Lithocarpus corneus

I mean, not me. In my studio. Found it at a flea market, I think, haven't figured out what to do with it. But now I have ideas! 🤗

I have some of the trapa bicornis seed beads and didn't have the ID for them.