- This allows answers to be much less vague - especially if it's a hard question, with multiple 'possible' answers. To allow for the voting up of a correct answer, and avoiding long discussions.
- It makes searching for a specific plant much easier (as a site user, or as someone searching online).
- It keeps the answers short and simple. Again, it should be easy as possible for others searching for the identification of that particular plant to find the answer easily.
If you post a picture including several species or varieties, please specify which one in particular you are asking about.
If you are interested in the identification of the species of a group of plants, such as (for example) a colorful zinnia mix, where they are all obviously the same species, but not variety, you can ask, as a whole, what plants they are. If you are interested in the particular varieties, you would be required to post pictures of each, in their own questions, to avoid being too broad
###You can post identification questions asking for a health diagnosis.
In that case, it can be appropriate to ask for the identification of 2 species (the affected plant, and the pest/disease). Proper tagging would include identification, diagnosis, and pests, diseases, fungus, insects, etc. The more specific you can be, the better.
In the case of parasitic plants, that is probably the only instance when asking for the ID of more than one plant species per post is called for.
###Posts asking for the identification of multiple plants should be closed as 'Too Broad'.
For new users, it would be good to leave them a nice comment, to let them know of this rule (you can link this post, or to the identification tag wiki, as a reference). If they don't take any action in altering their post, it can be closed.
And lastly, just as for any post that is considered off topic, please do not answer it (not even in the comments), as that does a poor job of educating the user, and increases the likelihood of them posting in a similar manner again.