Tree ID please.

[Raging Bull]

In my travels yesterday I found this seed. I'm in S.E. Qld on the Gold Coast. The seed pod was split open with the seed still inside. The seed is about the same size as an avocado seed, but not as round. I've included pictures of the tree it most likely came from as there were other seeds under it that had been crushed by cars driving over them. The only leaf I could access to take a picture was one that had been dropped and all others were too high on the tree to reach. The leaf is about 7 cm long and quite thick but not really leathery.
If anyone can ID this tree it would be appreciated, and if you know if it is suitable to grow as bonsai. Sorry about the quality of the tree photos, the 'phone camera is crappy.
Thank you, Frank.

[Shaady]

By no means am I an expert but those appear to be blackbean seeds, Castanospermum australe. I have never heard or seen of one as a bonsai but I have a seedling I germinated that I will at least attemp to bonsai.

[Raging Bull]

Thanks for the ID Shaady. I've googled it and it looks like a black bean seed, but the tree it was lying under has different leaves to a black bean. The seed pods are quite large, so I don't know how it got so far from the nearest black bean tree, which is a fairly small one of perhaps 6-8 meters and about 20 meters away from where I found the seed. There were several old seed pods under that black bean tree, but they all held at least three or four seeds when they were full, whereas the one I found had only one seed.
I will plant it and wait and see what, if anything develops. I'll post it when if I get a result.
Cheers, Frank.

[Shaady]

Don't bury the seeds very deep as they require light to germinate and prefer to germinate from on top or level with the soil. The seed pods can be quite variable in size and the seeds, while they did form an important part of aboriginal bush tucker they are poisonous without the appropriate treatment.

[Raging Bull]

Yes, I did some more searching and have more info on it now. It is definitely a black bean seed.
Cheers,Frank.