This one should be easy to ID because it has distinctive nodes at the base. More of a clumper than a runner (or at least it's slow growing and not very invasive). So far 15-20' tall, about 10 years old.
Here is a link that might be useful: Ph. aurea
Hmm, I noticed P. aurea is supposed to be a heavy spreader. Mine has stayed put (hardly moved 6' in 10 years) compared to my yellow groove bamboo (which is HIGHLY invasive). Wonder why?
Looks to me like Buddha's Belly Bamboo (Bambusa tuldoides) with very moderate "bellies". I'm going by the appearance of the foliage and the apparent size and color of the culms, as well as he shape of the lower culm. Another clue is that it is appearing on some culms, and not others.
It all depends. I had a small grove of Yellow groove that got no bigger than 8' wide by 5' deep over a 30+ year period. But I have also seen it go crazy in just a couple of years.
As far as the ID: I still think it's Ph. aurea. That's my story, and I'm sticking to it!
Definitely not any of the Buddha belly bamboo that I grow.
B. tuldoides does not have bellies and is known as Punting Pole bamboo here.
I strongly agree with Kudzu on the ID of Ph. aurea. There are countless groves of it down here in the wild and even mine has identical compacted nodes. A very common bamboo here, and it will not have the compressed nodes on all culms and the degree of compression varies also.
Buddha Belly aka B. vulgaris 'Wamin' always bellies except on thin whipshoots or culms less than 1/2 inch thick.
Another Buddha Belly aka B. ventricosa produces bellies when grown under stress or kept small, but never in an open grown specimen.
I do know that identical clones of bamboo can grow completely differently in different parts of the country. Soil, sun, nutrients, warmth, soil type, amount of fertilizer, etc all play a large part in grove growth.
You most likely have P. aurea.
P. Aurea often called fish pole because of the compressed nodes at base. Also notice there is an alternating groove.
An excellent observation...'alternating grooves', something that does NOT appear on any of the Bambusas, but on the Phyllostachys'.
...and on the rare Phyllostachys edulis 'Heterocycla'
Here is a link that might be useful: Tortoise Shell bamboo
The alternating grooves(sulcus) are generally a characteristic of the Phyllostachys'.
Dendrocalamus giganteus (variegated) also can have the compressed nodes as seen in the photo below taken by Elizabeth Haverfield. from Tropical Bamboo Nursery, Loxahatchee, FL.
I wonder how many bamboo are able to have compressed nodes, and/or what might cause the compressions...
Great photo. How big in diameter are those culms?
I'm not sure, but here's another pic taken by Richard Waldron, I believe of the same clump.