What the heck am I propagating???

Hi all. Here I was merrily collecting what I thought were tipuana tipu seeds all over the city to help build up my soil. Just on a hunch I decided to google some images of tipuana pods and they look NOTHING like what I've been collecting! I'm hoping someone will be able to ID the pod and seeds here and let me know if I've been wasting my time, or that I do in fact have something that may be of use to me anyway.

The tree appears to look for all intents and purposes like a tipuana tree.

I think it looks like a locust seed pod but without one to compare I couldn't be sure. I don't know what a tipuana tree looks like though...maybe like one of the locusts? thorns?

No thorns at all on the tipuana, which is why I kinda prefer it to the locusts. And no spikes on the leaves either.

Also, the tipuana is a quintessential Australian street tree and very common, whereas the locusts are almost unheard of except in boutique nurseries.

I've been googling Judith's locust suggestion, and came up with this:



Which is an article on the dreaded honey locust! I say dreaded because of Bill Mollison's infamous story about the town taken over by honey locust thorns. I definitely don't want honey locust, so we may need to "gift" the dozens of honey locust seedlings and start again...