Mammillaria karwinskiana ssp. nejapensis
Mammillaria Nejapensis var. longispina or Silver arrow cactus is a slow-growing, dark green cactus that bears long, silvery-white spines and small, silvery-white hairs.
Stems are globose to short cylindrical, somewhat wider in the upper part, blue-green to dark green. Becomes slightly columnar to 6" in height, branching dichotomously (each single stem begins to divide to form two stems) to form large clusters. A cream coloured 'snowy' tomentum is present on the top of the plant.
Flowers are pale yellow with reddish midstripe on each petal...
Mammillaria species like most cacti they're drought tolerant and need very little care and attention to grow well . Plenty of sunshine will keep this cacti more than happy. Provide bright, even light to encourage tight growth and flowering. Some shade during a hot summers day can be helpful to prevent sunburn.
Allow the soil mix to become nearly dry between watering, but then water thoroughly. Suspend watering in the winter, but mist occasionally. Not enough sunlight and over-watering are common mistakes.
Use pot with good drainage and a very porous potting media.
Feed every 4 weeks with a high potassium fertiliser during summer
Suited for window sill and dish gardens