What is mycorrhiza? Is this a plant?

What is the name of this plant?

• I need help finding the name of this certain plant. I spotted it while I was on a school field trip. I didn't have any pictures of it so I hope I will be able to describe it enough. So this plant is grown in South East Asia on a hot & wet climate on a sandy environment. The plant is about 1m tall. It has multiple green leaves on its stem. The fruit (I think its a fruit) is shaped like a short cylinder sort of like a short bean. The fruit is maroon color on the top and light green on the bottom. It has multiple,small green seeds inside (at least 18). There was a same plant with a dry fruit. When shaken, it sounds like a rattlesnake most probably because the seeds are dried up inside the fruit. I think it is categorized as a sun plant or a shade plant. Again I'm sorry if the description doesn't describe the plant well enough.

• Answer:

  It may be a CAROB , you can type the name on google images and check for yourself if it matches.