Flesh From Wood

With a skin of thick bark and leaves growing at their extremities, you could be forgiven for believing that mandrakes are simply bizarre plants, treants, or animated trees. This might even be partially true: it seems that while mandrakes originated from some plant ancestor, they have become something midway between animal and plant through some strange magic or stranger evolution.
Mandrake anatomies are filled with paradoxes. They bleed a ruby ichor, reminiscent of both blood and sap. Their hearts, which look like a knot of roots, pump this around their body, enriching it with oxygen borne by leaves and special pores on their extremities. By preference, mandrakes can bask in the sunlight or consume living things for nourishment, and can even absorb nutrients through their feet, though they rarely subsist by sunlight and water alone.  

Forest Envoys

Alchemists and arcanists alike scratch their heads at mandrakes, but druids know them as the green emissaries who stand between the realms of animals and plants, making peace for all parties. To druidic tradition, mandrakes are unique, ancient constructions of Mother Nature herself, intended to act as delegates for her will. Mandrakes are credited by old druids for aligning elves with the forests and dwarves with the mountains; only with the rising tide of humanoids and their preponderance of gods did most creatures forget about Mother Nature and her half-plant ambassadors.
Today, mandrakes are rare, and make their homes in the forests near where villages and cities meet the true wilds. Humans tell tales of mandrakes savaging those who enter their domain, but druids and those who respect the old traditions of the forestknow that such ire is seldom undeserved.