There is no one species of bamboo leaves used to wrap the rice.

You can use any large-leaved bamboo for this purpose. Banana, reed, and even palm leaves are used also.

Kt

I'm not certain that bamboo leaves are used at all because even the bigger ones aren't that big and they are rather thin. I believe banana leaves are most typically used.

Thank you for the feedbacks. I spent about an hour googling and found a potential bamboo that might be what I'm looking for. It's called Indocalamus TESSELLATUS. Some websites say that its leaf is used to wrap food. But I don't know if it is the one that my mom used, so I'm ordering it. What I remember was that the bamboo was sold as dried leaves in a package. It has slight fragrance.
The following website has a picture of the leaf:
http://www.gourmetsleuth.com/equivalents_substitutions.asp?index=B&tid=2315

Well now I know something new. I've only seen Asian food served with broad leaves and wasn't aware that things like Chinese dumplings were sometimes wrapped. As for the I. tessallatus, that has the largest leaves of bamboo under cultivation. I don't know about their fragrance, but it will probably be the best size to work with. Below is a link where you can look at pictures of this species. Good luck.

Here is a link that might be useful: I. tessallatus

Thanks kudzu9, we all learn something new everyday. That's why I like this forum so much. Didn't realize that you are also in WA. I'm in Auburn:-)
Maybe that website you suggested will have a picture of tessallatus with a location in WA soon:-)

It popular in Japan years ago to wrap rice ball with Bamboo sheath not Bamboo leafs.
Bamboo Sheath help protect bacteria/spoil while carry them around.