Mammillaria parkinsonii, also known as owl-eye pincushion or owl-eye cactus, is a species of flowering plant in the family Cactaceae. It is endemic to Queretaro, Mexico. Mammillaria parkinsonii is listed as Endangered due to a limited distribution (extent of occurrence ca 2,500 km2), severe fragmentation, a continuing decline due to illegal collection, and degradation of its habitat across its range. Clarification of the taxonomic status of this species is a research priority. In height, the stem is up to fifteen centimeters, in diameter eight. The tubercles (papillae) are pyramidal, hard, with a milky juice, which are up to one centimeter long. Areoles are round, at first strongly pubescent, eventually glabrous. Axilli ((from Lat. axilla — "armpit") - the sinus between the papillae (mamillae) or tubercles) with white hair and wavy bristles. Radial spines, in the number of twenty to thirty-five, snow-white, bristle-shaped, from three to seven millimeters in length. The central spines are two in number, but there are up to five pieces, the upper one is up to eight millimeters in length, the lower one is up to two centimeters. The flowers are creamy, funnel-shaped.