Origin and Habitat: Mexico (Tamaulipas) It grows near Tula San Luis de Potosi, Rancho el Vergel. The wild population is less than 250 individuals confined to a single location less than 1 km (100x200 m), where it continues to decline as a result of illegal collecting.

• Turbinicarpus ysabelae (K.Schlange) V.John & Říha
• Gymnocactus ysabelae (K.Schlange) Backeb.
• Neolloydia knuthiana var. ysabelae (K.Schlange) A.T.Powell
• Pediocactus ysabelae (K.Schlange) Halda
• Thelocactus ysabelae K.Schlange in Croizat
• Turbinicarpus saueri subs. ysabelae (K.Schlange) Lüthy

• Turbinicarpus ysabelae (K.Schlange) V.John & Říha
• Gymnocactus ysabelae (K.Schlange) Backeb.
• Neolloydia knuthiana var. ysabelae (K.Schlange) A.T.Powell
• Pediocactus ysabelae (K.Schlange) Halda
• Thelocactus ysabelae K.Schlange in Croizat
• Turbinicarpus saueri subs. ysabelae (K.Schlange) Lüthy
• Turbinicarpus ysabelae var. brevispinus (K.Schlange) V.John & Říha
• Gymnocactus ysabelae var. brevispinus (K.Schlange) Backeb.
• Thelocactus ysabelae var. brevispinus K.Schlange

• Turbinicarpus ysabelae f. cristatus
• Gymnocactus ysabelae f. cristatus hort.
• Neolloydia knuthiana var. ysabelae f. cristata

Description: Usually solitary cactus almost completely concealed by spines and wool.
Stem: Globular depressed, 40-160 mm high, 70-200 mm wide, yellowish-green with a very woolly apex.
Ribs: 15-15 tubercled.
Tubercles: Conical, well-developed, 3-8mm high.
Areoles: Oblong, at first very woolly then almost naked.
Radials spines: 16-20 radiating, partially pectinated, straight, whitish 2-10 mm long. The young spines have a yellow base, a white median zone and a dark brown tip, then they become white and translucent.
Central spines: 1 curved upwards, at first black-bluish that becomes greyish-white with darker tip 7-20 mm long.
Flowers: White with a greenish base, 10-18 mm long, generally 30 mm wide but can be up to 70 mm wide.
Fruit: Dry, dehising from a lateral fissure.
Seeds: Black.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
2) Nathaniel Lord Britton, Joseph Nelson Rose “Cactaceae: Descriptions and Illustrations of Plants of the Cactus Family” vol. 4 The Carnegie Institution of Washington, Washington 1923
3) James Cullen, Sabina G. Knees, H. Suzanne Cubey "The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass" Cambridge University Press, 11/Aug/2011
4) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006

Cultivation and Propagation: This species is relatively easy to cultivate. Requires full sun and careful watering to keep plant compact and low. It has a tap root, and watering it properly is often difficult and tends to crack open or rot if over-watered.
Propagation: It can be reproduced by seeds. Young seedlings are tiny and they need several years to reach adult size, and require very careful watering.