Leuchtenbergia principis

This plant is originally from central to Northern Mexico. Can get up to 70 cm tall. It produces a beautiful pale yellow flower, sometimes a good amount of sun will induce the flowering. Be patient and you will be rewarded with this beautiful flower.

Recommended temperature zone: USDA: 9-10
Frost tolerance: Hardy to 20° F (-7°C)
Sun exposure: Full sun to light shade
Origin: North-central Mexico (San Luis Potosi, Chihuahua)
Watering needs: Water carefully, lack of water will make the tip of the tubercles yellow. Too much water will make it rot.
Propagation: Seeds, cuttings, offsets
Blooming habits: 3 to 4" wide (7-10 cm) yellow or pink flower at the tip of the tubercles. They are followed by green smooth fruit. When ripe the bottom of the fruit opens and releases several hundreds large seeds.

Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz