Plant Description
Plants may be solitary or part of small clusters; they are small and often in grasses or bushes so are often overlooked unless flowering. Mammillaria grahamii is protected in Arizona.
Central spines hooked, stems greater than than 1-1/2 inches in diameter, flowers in a ring below the apex, outer tepals minutely fringed, plants unbranched or branched and green or yellow-green stigma lobes distinguish this Mammillaria sp.
Habitat
Desert scrub; grasslands; interior chaparral; oak woodlands; alluvial slopes; hills; canyons; silty, sandy, gravelly, or rocky soils of igneous or calcareous origin.
Flowers
Light pink edges with darker pink centers and yellow-green to green stigmas. The flowers are arranged in a circle around the stem below the apex.
Stems
Solitary or in small clumps of 0 to 9 stems, 2 to 6 inches tall, 1-1/2 to 3 inches wide.
Areoles
These are structures unique to cacti, found on the stems, areas from which spines, flowers and fruits emerge.
26 to 33 spines per areol. Areoles are at the end of tubercles which are fairly well visible through the spines, unlike the more densely covered mammillaria tetrancistra.
Mostly bristly white radial spines but with 1, 2 or 3 longer and more central spines that are dark red-brown in color and strongly hooked at the end.
Fruit
1 inch long smooth red fruits.