Origin and Habitat: East of Brewster County, Texas, USA (?).

• Echinomastus kakui Backeb.

• Echinomastus warnockii (L.D.Benson) Glass & R.A.Foster
• Echinocactus warnockii (L.D.Benson) D.Weniger
• Neolloydia warnockii L.D.Benson
• Pediocactus warnockii (L.D.Benson) Halda
• Sclerocactus warnockii (L.D.Benson) N.P.Taylor
• Echinomastus kakui Backeb.
• Echinomastus pallidus Backeb.
• Echinomastus erectocentrus var. pallidus (Backeb.) Weniger

Description: Echinomastus kakuiSN|32477]]SN|32476]] is an invalid name (nom. inval. Art. 36.1, 37.1) published by Backeberg in 1963. It is one of the morphological or local forms of Echinocactus warnockiiSN|32472]]SN|32472]], and the two plants are not readily distinguishable, if not for the geographical provenance. More likely they are one and the same species. The provvisional name was Echinomastus pallidusSN|32476]]SN|32477]].
Stem: Spherical, slightly columnar, about 8 cm tall and 5.5 cm in diameter, pale grey-green, with spines interlaced above the apex.
Ribs: 13, divided into nipple-shaped tubercles, closely adjacent to each other, tubercles spiralling, up to 1 cm long.
Areoles: Up to 2 cm long, oblong-rounded, with gray-brown felt, later glabrous.
Radial spines: 10-14 up to 2.5 cm long, needle-like, interlacing, horn coloured with violet-gray tips.
Central spine: 1 robust, about 1.5 cm long, strongly pointing upward, violet-gray.
Flowers: About 2.5 cm long and 2 cm in diameter, whitish to creamy, with a faint pale pink midstripe on each petal and a greenish centre. The pale flowers appear most heavily in late winter and early spring.
For more details, see: Echinocactus warnockiiSN|32472]]SN|32472]]

Bibliography: Major references and further lectures
1) Walter Haage. “Kakteen von A biz Z”
2) “CACTACEES Echinomastus kakui Backeberg” Texte, photo & collection : Joël Lodé. © Edisud, Aix, 1994. Série 15 web: https://www.cactuspro.com/biblio_fichiers/pdf/Lode/LodeC-Acanthocalycium-Ferocactus_O.pdf
3) Echinomastus kakui Backeb. - Descr. Cact. Nov. 3: 6. 1963

Cultivation and Propagation: Echinomastus kakuiSN|32476]]SN|32476]] (Echinocactus warnockiiSN|32472]]SN|32472]]) is a most beautiful cactus but rarely seen in cultivation. It is quite difficult to grow on its own roots. Very easily rot! It’s thought that’s better to watch this species in photo or in the natural habitat rather than to try to cultivate it. For this reasons the plant is often grafted on a frost hardy stock.
Soil: Use mineral well-permeable substratum with very little organic matter (peat, humus). It needs perfect drainage to flourish.
Repotting: Repotting every 2-3 years. As it is especially prone to rot under-pot in a smaller container filled with very porous compost. Use pot with good drainage.
Exposition: This plant need full sun and above all a very good ventilation, especially in winter. Tends to bronze in strong light, which encourages flowering and heavy spine production.
Watering: Water sparingly during the growing season and keep totally dry during winter. In the rest period no high atmospheric humidity!!Care must be taken with watering as they tends to become swollen and untidy in growth habit if given too much water and shade.
Fertilization: During the growing season enrich the soil using a fertilizer rich in potassium and phosphorous, but poor in nitrogen, because this chemical element doesn’t help the development of succulent plants, making them too soft and full of water.
Hardines: It can tolerate temperature below zero (-15° C or less).
Pests & diseases: It may be attractive to a variety of insects to watch for:
- Red spiders: Sensitive to red spider mite. Overhead watering is helpful in controlling mites.
- Mealy bugs: Occasionally mealy bugs they develop aerial into the new growth among the wool with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.
- Rot: Rot it is the major threat. If the plants are not watered and “aired” correctly, fungicides won't help all that much. Mature individuals - if the growing conditions are not optimal, easily rot and die.
Remarks: Displaying your cacti on shelves has the added benefit of keeping them off the ground and away from potential rodent or snail damage.
Propagation: Seed or grafting. Seeds germinate in 7-14 days at 21-27° C in spring, remove the glass cover gradually as the plants develops and keep ventilated, no full sun for young plants! The seedlings should not be disturbed until they are well rooted, after which they can be planted separately in small pots. Seeds are relatively difficult to germinate (only a limited percentage of seeds germinate). Grafting is often used to speed growth rate and to create a back-up for plants in collection.