The plant lacks ribs, and its wide, flat cusps have small areoles (2–3 mm) with no spines.

[6] This species is the southernmost representative of the genus Lophophora, thriving in limestone soils within a small area of approximately 775 km² between Vizarrón, Bucareli, and Tolimán in Querétaro, Mexico, with minor occurrences in Hidalgo.

Its natural habitat is semi-deserts on slopes and river beds, and under the shade of various shrubs and nurse plants such as Larrea tridentata and Senegalia sororia.

[5][7] It grows at altitudes of 1,000–2,000 meters above sea level, forming isolated and self-regulated populations in the Estórax River depression.

The epithet diffusa derives from Latin, meaning "indistinct," referencing the plant’s low, flat, and barely noticeable warts.