Explanation: Serpentine aster (Symphotricum depauperatum) A large proportion of state-rare plants are considered rare because they occur only in specific habitats that themselves are uncommon.
Answer:
A large proportion of Serpentine aster (Symphotricum depauperatum) are considered rare because they occur only in specific habitats that themselves are uncommon. These plants occur in Pennsylvania only in a few sites in Chester and Delaware counties because they support a unique set of nutrient-poor soil.
