>> Of course if there is one plant without a label, that's the one they want to know about!!!
>> The members all want to know the names and the Latin ones at that!
Here are some last-resort names. I looked up Latin words for "no name", "double talk" and "forgotten". You could give one of those as the species or variety name, winking as you do.
Sine nomine - without a name
Geminus loquitur - "double talk"
oblitus - for one man or boy.
oblita - for one woman or girl.
obliti - for two people, one or more male
oblitae - for two or more females
oblitum - for one specific thing/event
oblita - several events or things
obliterabitur (will be forgotten)
example: "Obliterabitur amphigorum*"
* Amphigory definition: a meaningless or nonsensical piece of writing, esp. one
intended as a parody.