Hi CS!
You can just go ahead and do that yourself.
First, you have to submit a request to add it, with the binomial name you already have.
Go to the plant database and search for it to be sure it isn't there under a similar name already.
When I did that, I found a plant with YOUR name as a synonym:
Senita (Pachycereus schottii)
If you think that IS the same plant, you can add your photo and info to that entry.
If you disagree, you can either submit your request anyway and see what they say, or ask a moderator directly in a forum or via tree mail whether they think the synonym is a "good" synonym, or whether there really are two different plants sharing a synonym.
A moderator will review each new plant submission, then
approve it if they agree it is new to the database.
Plant naming has become even more complicated since taxonomists started changing names as often as they change their socks! I'm glad when DNA evidence gets innocent people out of jail, but I wish we could stop changing names every other week!
The names have been changed to confuse the innocent!
After a new plant submission is approved, THEN you can go back to it and add info, like where you saw it, and add the photo, plus any data details or comments you have. Like why
Lophocereus schottii might NOT be the same as Senita
(Pachycereus schottii)