Hard to be certain from a pic of cut stems, but that looks more like Chinese golden bamboo to me. It's naturalized all over the south. You can make good arrows from it, but you have to be picky cutting it to find shafts that are the right size , don't have too many nodes, and aren't really flat or sulcate on one side. Don't be afraid to grind those nodes down even with the rest of the shaft. I do it to all my cane arrows and haven't broken one yet. Knocker, native river cane can reach nearly 30' high and 3" in diameter under ideal conditions, but it's rare to see it that size. Most of it around here maxes out at about 10'-15' tall and about 3/4" in diameter. To get good shafts, you have to use the part between the ground and where the heavy branches start, so you usually just get one shaft per stem.