The Venus flytrap gets the "Venus" part of its name because its flowers are really pretty (like the goddess Venus) and are white, like the planet Venus in the sky. The plant is not from Venus. The "Flytrap" part comes from its obvious bug-eating attributes.
This is, however...what shall I call it? A "comfortable fallacy." You often see this story maintained in books about carnivorous plants, but this is because of an article that John Ellis wrote in 1768. This is what you would call a cover story:
"...and from the beautiful Appearance of its Milk-white Flowers, and the Elegance of its Leaves, thought it well deserved one of the Names of the Goddess of Beauty, and therefore called it Dionaea."
All of that is well and good, but pretty much a fairy story.
It appears that the 'Venus' part comes from a glossing-over of the original and more earthy comments of the researchers of the time. Apparently they were trying to make it 'politically correct' in the terms of the mores of the times...
The true reason that Venus is part of this plant's name due to the dirty minds of the kooky naturalists and nuserymen (such as John & William Bartram, Peter Collinson, William Darlington, Arthur Dobbs, John Ellis, and Daniel Solander). When they looked at the plant, they saw in its amazing behavior and attractive form (two red, glistening lobes, surrounded by hairs, sensitive to the touch), something that reminded them of female genitalia of their own species. Indeed!
[emphasis and links my addition]
saracenia.com
Further observations:
The Venus flytrap, however, closed its leaves for an obvious reason–to capture and devour insects. Here was a brand new kind of entity: an actively carnivorous plant. Ellis enclosed a picture of the Venus flytrap, which he called Dionaea muscipula, with his letter, showing a living specimen, with a caterpillar and a moth in the throes of being digested; in a caption, he described the leafy snare as a “Rat trap with teeth.” So that the rest of the world could appreciate the Venus flytrap, Ellis published his letter the next year in a pamphlet called Directions for Bringing over Seeds and Plants from the East Indies and Other Distant Countries (1770). It includes a colored engraving of Dionaea muscipula
-John Ellis
footnotes
Phil Sweet contributed at least half of the very interesting information attached to this post. This is a fascinating topic and deserves more and constant updates...
Links often rot, and the more we can add to this answer the better it will be.
An incredible wealth of information on the topic
This is a community wiki, so if you have good info feel free to contribute...
