From the rarely-so-thoughtful-but-often-fun Overheard in New York:
So Yada Yada Yada, We Spent the Night in the E.R.
Twin sister #1, indignantly: I tried to get him the least sexual plant I could find. I mean, a cactus, how much less sexual could you get?
Twin sister #2, thoughtfully: You really can't get any less sexual than a cactus.
–Uptown 1 Train
Though to be fair, even cacti do have sex…