schreef
I have a question about what plant names to capitalize. I am
identifying weeds and pests in lawns and i am using plant names in the
subject header. I already know that the genus name is capitalized, but
the species name is not. And the two are usually italicized.I f for
example i am using the name of a grass such as tall fescue, would it be
capitalized if not used at the beginning of the subject header since it
is just a common name? Hope i made sense.

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There is no agreement on that. The advantage of capitalising common names is
clearest when the first part of the name is a common adjective (red, blue,
little, tall, common): in such cases capitalizing, e.g. Tall Fescue makes it
clear that the entire phrase is a name. This as opposed to tall fescue which
could be a tall specimen of fescue.

There are geographical and cultural differences in usage (capitalize
yes/no). I would suggest: if in doubt do capitalize.
PvR