Botanical or botanic gardens?

Factual Questions
1

I was looking up something for another thread, and was trying to look up the Botanical Gardens in Washington DC. Well apparently it doesn’t exist. But lo, there is a Botanic Garden…

Now I’ve never heard of that before. I’ve always heard “botanical.” Anyone have any idea why there are two very similar terms (apparently both commonly used) to describe the same thing?

2

I think you are right: it’s BOTANICAL. I vaguely remember the rule: noun>-ic>-ical. That is, like in history>historic>historical.
If something will go into the history, it is labeled “historic”, the next category would be “historical”, because it’s one step removed from history, it relates only to “historic”, not to the history itself.
So, I think, in this case it’s “botanical”: the science is botany, the related field is botanic, the gardens relate to the field, not to the science itself, therefore its “botanical”. The classification of plants would be “botanic” classification.
But I’d like to hear from a pro linguist.

Peace

3

The OED says that “botanical” has superseded “botanic” in everyday usage. Both words mean the same thing now.

“Historic” and “historical” still have different meanings. An Historic Museum would be a museum that is famous because of its nature, like the Louvre. It’s an historic building because it’s old and has had famous artwork in it.

A(n) historical museum would be a museum devoted to events in history, like the Smithsonian’s Museum of American History.

I don’t know why “botanic” and “botanical” don’t have this distinction anymore. Perhaps botany isn’t as popular as history?

4

The one in New York City is the Brooklyn Botanic Garden, according to my membership card and other material they’ve sent me. I guess that both are still valid for that sort of use.