Publication: Acta Mus. Richnov., Sect. Nat. 7(1): 39 (2000)
Description
Thelocactus hexaedrophorus subs. kvetae (firstly described by Chvastek & Halda in 2000) is a local or morphological form of the widespread and variable Thelocactus hexaedrophorus distinguished by flattened discoidal bodies, bright purple-pink flowers and larger seeds.
Taxonomic notes: Thelocactus hexaedrophorus subsp. kvetae and the very similar-looking Thelocactus hexaedrophorus subs. jarmilae more likely belong to one and the same subspecies. They both have pink flowers and grow in the more eastern part of the distribution area of T. hexaedrophorus. Admitting that the pink flowering form deserves a separate status, we have the choice between subsp. kvetae and subsp. jarmilae. However a pink-flowering form was earlier described by Lemaire in Labouret, Monogr. Cact. 251. 1853 as Echinocactus hexaedrophorus roseus. So it would be better do not use one of these new published names, but just use the old name. “Roseus” means rose coloured and indicates the pink colour of the flower. The name E. hexaedrophorus roseus was first published and therefore it should have the priority. Another “subspecies” Thelocactus hexaedrophorus subs. franci has pink flowers and it should also be synonymized with E. hexaedrophorus roseus.
Origin and Habitat
Thelocactus hexaedrophorus subs. kvetae comes from near Rio Verde, in the state of San Luis Potosi, Central Mexico.
Altitude range: Around 1200 metres above sea level.
Habitat and ecology: This subspecies grows on the top of a limestone hill.
Cultivation and Propagation
This cactus is easy to cultivate and recommended for any collection that needs lots of light with ample airflow.
Growth rate: It is a small growing, but easily flowering species. It offset from the base and can fill a 25 cm pot in just a few years given the best conditions.
Soils: It likes very porous standard cactus mix soil with little organic matter (peat, humus).
Repotting: Repotting every 2-3 years. It will need a pot with sufficient depth to allow the tap root. As it is especially prone to rot under-pot in a smaller container filled with very porous compost. Use pot with good drainage.
Watering: Water regularly in summer, but do not overwater (very wet-sensitively, especially in light of its succulent root system). Its roots are easily lost in pots that stay damp for any length of time. Keep dry with ample airflow in 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.
Hardiness: Reputedly sensitive to frost , but less so if kept on the dry side prior to, and during, cold weather (hardy to -7° C for short periods). However some warmth throughout the year will increase the grower’s success (minimum 5° to 8°C during rest season).
Exposition: Outside bright sun, filtered sunlight or afternoon shade, inside it needs bright light, and some direct sun. Subject to sunburn if exposed to direct sun for too long. Tends to bronze in strong light, which encourages flowering and heavy wool and spine production.
Uses: It is an excellent plant for container growing. It always looks good and stays small. It look fine in a cold greenhouse and frame.
Pests & diseases: It may be attractive to a variety of insects, but plants in good condition should be nearly pest-free, particularly if they are grown in a mineral potting-mix, with good exposure and ventilation. Nonetheless, there are several pests 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.
- Scales: Scales are rarely a problem.
- Rot: Rot it is only a minor problem with cacti if the plants are watered and “aired” correctly. If they are not, fungicides won’t help all that much.
Reproduction: Nearly always from seed, since the plant rarely produces plantlets.
Bibliography
Major references and further lectures
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Rob Bregman en Rikus van Veldhuisen “DE NIEUWSTE ONTWIKKELINGEN DEEL 5. THELOCACTÜS HEXAEDROPHORUS VAR. ROSEÜS. EEN KEUZE TUSSEN THELOCACTÜS HEXAEDROPHORÜS SSP. KVETAE, FRANCII, JARMILAE OF VAR. ROSEUS” Succulenta 85: 252… 2006
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Alsemgeest, W., Bregman, R. & Van Veldhuisen, R. (1995). “Het geslacht Thelocactus - 5. De vormen van Thelocactus hexaedrophorus.” Succulenta 74: 274 - 279.
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Chvastek J. (2000). “Thelocactus hexaedrophorus (Lemaire) Br. & R. subsp. kvetae J.Chvastek et J.J. Halda.” Acta Musei Richnoviensis 7(1): 39.
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Halda, J. (2000). “Thelocactus hexaedrophorus (Lemaire) Br. & R. subspec. francii Halda et J.SIadkovsky.” Acta musei Richnoviensis 7(1): 38.
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Halda, J. (2000). “Thelocactus hexaedrophorus (Lemaire) Br. S R. subspec. jarmilae J.J.Halda et J. Chvastek.” Acta Musei Richnoviensis 7 (1) :38.
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Lemaire, C. (1839). “Echinocactus hexaedrophorus Lemaire.” Cact. Gen. Nov. Sp. 27.
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Pilbeam, J. (1996). “Thelocactus. The Cactusfile handbook no. 1” Cirio Publ. 1 Stadhouderslaan 3, 3417
