Abstract: A new and unique variety of the mushroom Agaricus subrufescens Peck was produced by crossbreeding a single spore isolate from the fungal strain ‘I-101’ and a single-spore isolate from the fungal strain ‘SBRFG’. The resultant hybrid, named ‘H1X1’, exhibits early cropping, large size, high productivity, and an attractive appearance that includes a smooth, round cap.