Those two taxa
have similar external morphology, but Chung (1955) presented
P. ullungdoensis as a new species as it had hair on the base
of lepicena. Recently, Jung (2008), and Jung and Chung
(2008) did not acknowledge existing characteristic as a
trait, and divided them based on the shape of inner glume
surface, but as those two studies did not mention the type
specimen and only arranged on-site investigation, hard to
figure out the exact nature. Therefore, it is judged that it
would be necessary to conduct more detailed comparative
study between the two species.