Fissiparous - origins of the word

I know what “fissiparous” means, but I haven’t found any satisfactory explanation of its origins.

My curiosity about this was (re)kindled by reading the following section of that British newspaper, The Guardian:

“As I have written before, I am not confident that a leadership that is frightened of saying boo to a goose will win the next election. But it seems blazingly obvious that the fissiparous Conservative party is doing its best to lose it – probably with a little help from the ghastly Nigel Farage and the so called Reform party”.

Best wishes for a pleasant Sunday.