You might get some clues about the gall (or whatever) by cutting it open. It looks like whomever was there left already...I'm just gonna go stand over there when you do it :) If it's a blackberry or similar the correct plant forum here might know what it is.

I checked several resources, and this does appear to be Miscanthus. Saccharum has a central inflorescence axis that is much longer than the branches. Its spikelets shed in pairs, along with joints of the inflorescence axis. Miscanthus has a central inflorescence axis that is shorter than the branches. Its spikelets shed singly, leaving the persistent inflorescence axis. If you want to see what the dried heads look like, try these searches: Saccharum ravennae spikelets Miscanthus sinensis spikelets

Sagittaria graminea, Grassy arrowhead. See here: https://en.wikipedia.org/wiki/Sagittaria_graminea

I use google lens for suggestions sometimes, and it can give me good leads?(sometimes), but other times can be light years off, with absolutely ridiculous results. Does anyone know if Seek is all AI, or do they have people at I naturalist that give the answers for seek? I know a couple people who are credited with thousands of ID'S at I nat . One of them used to be a regular contributor at this forum. I'm thinking Google lens learns from all my internet searches and thus over time gets smarter. I asked someone who was praising a plant app, if they would still remember the plant species, if they ran into it a year later, and were without their app. I don't think much plant knowledge is retained if you rely on an app. I don't understand why a lot of people boast about their apps. You're basically stating that you let a machine do the thinking for you, so nothing about that is something I would be proud of. I respect and admire those who come up with correct ID'S from their own minds and stored knowledge. I totally agree with Ken about apps replacing human discussions, ( teaching, learning), and taking all the fun and enjoyment out of plant Identification.