Final answer:
The two understory plants in the piney woods are ferns and mosses.
Step-by-step explanation:
The two understory plants in the piney woods are ferns and mosses. Ferns are considered an early lineage of plants that thrive in damp and cool places, such as the understory of temperate forests. Mosses, on the other hand, can dry out in drought conditions but can quickly absorb water when it becomes available.