Alas, Rick Kerrigan just clarified In his HBMS zoom meeting (02/17/21) that A. inapertus and A. gemellatus have identical ITS sequences. According to Dr. Kerrigan this is not problematic but rather indicates that the morphological distinction occurred faster than the ITS could evolve.
Agaricus inapertus = Endoptychum depressum
Growing near pine trees. Cap- 11 cm at widest, pinkish streaks, margins enrolled. Gills firm with lots of short gills. Stalk narrows at base, approx. 13 cm long. Has odor (kind of like radish)