I can't really say but I will give you my opinion. I don't think he had any inspiration for making any of the flowers. When he started writing the script in 1994, I think he was more concentrated on the plot and the characters then the flowers. He probably just had a team of artists that worked together on designing the flowers.
posted over a year ago
I read somewhere that Cameron himself remember the colorful and interesting plants he saw once while scuba diving. And like you say, probably had artists design them from there.