Hi Terri,
Thanks for writing with this question.
You're right hat the comment was a good comment and is helpful to anyone who visits that plant looking for information. According to my logs here I see that you did get an acorn for posting that comment.
The other comment you posted, about the Rumex acetosella, did not result in an acorn because it was shorter than the system gives acorns for (the system only gives an acorn for comments that are paragraph length or longer).
I hope this answers your question.