The following phrases are colloquialisms, idioms or proverbs that are written in their literal, and rather complicated form. Can you uncover their true meanings and solve this teaser?

Example: "Don't place the two wheeled vehicle in a position preceding the equine mammal," is the proverb "Don't put the cart before the horse."

1. Positive aesthetic appeal is solely the equivalent of the thickness of the epidermis.

2. The ground covering of slender leaved plants is always a more vibrant hue of a common secondary color in the proximity of the opposite surface of a structure serving as a boundary.

3. Produce the sound of sharp tapping by striking blows to a processed piece of secondary xylem from a large perennial plant.

4. The gyre that emanates shrill sounds receives the viscous lubricant.