Lions (Panthera leo, not pumas) have a pretty acrid odor. But they don't live where the OP was hiking. Never smelled a cougar in heat or when scent-marking.

Plants don't growl. He heard a distinct growl.

I think it was maybe a bear, maybe a cougar, maybe the skunk ape. If he'd found tracks later, that would help.

I'm glad he warned the other hikers. Even if plants emitted the odor, they may have done it because a bear was grazing them. Or the skunk ape, in which I about half believe.

I bet that 10mm goes on his next hike!

I've had a gray fox growl at me and look pretty hostile. I drew my M-66-3 and walked wide of him, trying to avoid eye contact, He finally walked off, too. About a week later, this same (?) fox stood on a high point and challenged me, snarling. Again, I drew the .357 and walked wide of him, and he seemed satisfied. But he came pretty close to being a field test of Federal's 158 grain .357 Hydra-Shok.

I called the Natural History Museum and asked if the mammalogist on the line thought the fox might be rabid or was just being territorial. He agreed that it was probably the latter.

Later, in that same area, a female fox gave me a wary eye as we both kept some distance and went opposite ways on that path. I saw her or another vixen much later, with kits. Cute little buggers. That mom didn't see or scent me, and it may be just as well. I don't know how she'd have reacted with the kids there.

None of these foxes emitted any special odor, but the male was a real growler. They may well have scent glands that emit a musky smell and just didn't use it.

If I heard a growl from the region where I smelled dead or rotting meat, I'd suspect a bear on a kill or scavenging on a dead animal it found.

You could call a museum or zoo and describe he circumstances and the smell, the nature of the growl, etc. They might have an idea. An ornithologist at the museum asked me where I'd heard an owl and how it sounded when it called and what the circumstances were. He used that info to tell me that it was screech owls that I was hearing. Later, a Great Horned Owl flew right at my face and veered off at the last split second as it realized that I was sitting behind the windsheld of my parked car. It twanged the antenna pretty badly as it swerved to avoid the glass. That was a very differen owl. I still wonder what it thought it was doing. Maybe it saw my face in the darkness and thought it was a small animal? Scared me pretty badly. By the time I saw it coming, it was right there!