P. nigrispina is a globose-shaped cactus, with a lively green stem. This one is entirely covered by thorns, and its ribs are very regular. From the white and woolly areolas come out several thorns, some thin and yellowish and others more robust brown/reddish. P. nigrispina expands to form new clusters. Its magnificent large flowers are yellow and silky, creating a very pleasant visual impact.