Inspired by @NumbahTwo I was thinking of this today, and your list made me laugh, even though it's in a different vein.
  1. Any plants with leaves big enough for a medium sized dinosaur to notice.
  2. Plants with flowers at least as big as my hand.
  3. Plants with bright orange spiky neon flowers
  4. Flowers that look innocent but have sticky undersides that trap and cling
  5. Plants that look soft but bite you when you touch them
  6. Plants with burrs that cling to your clothes and you can never get rid of them
  7. Any plant that looks like it wants to eat you
  8. Plants that smell delicious but have poisonous reputations
  9. Plants that want to leave their seeds EVERYWHERE