Accepted Scientific Name: Gymnocalycium pugionacanthum Backeb. ex H.Till
Kakteen Sukk. 38: 191 1987
Gymnocalycium catamarcense f. belense Photo by: Peiffer Clement
VS 64 (Collector Vladimír Šorma) Cuesta de Belen, Catamarca, Argentina, 1200m.
Origin and Habitat: Belén to Hualfin and adjacent areas, Catamarca, Argentina
Altitude range: 1000-1900 metres above sea level.
Habitat and ecology: Gymnocalycium catamarcenseSN|22552]]SN|22552]] f. belense grows on rock interspersed slopes.
Synonyms:
See all synonyms of Gymnocalycium pugionacanthum
Description: Gymnocalycium catamarcenseSN|22552]]SN|22552]] f. belense (firstly described by Backeberg H.Till & W.Till 1995) is a local or morphological form of Gymnocalycium pugionacanthumSN|22551]]SN|22551]]. The name G. pugionacanthum can be validly applied to plants from Cuesta de Belén and the surrounding hills. The typical form appears exclusively along the southern and south-eastern slopes of the Cumbre del Venado, Cuesta de Belén and the low alluvial hills west of Cuesta de Belén. These plants has been described as bearing a very particular spination: perfectly pectinated spines, short and strong, rectilinear, dark to very dark at their extremity and white in their proximal half. However the population is not homogeneous and some subjects have spines that are longer, thinner, more or less rcurved and clearer. M. Meregalli & Tomáš Kulhánek (2015) point out that the subjects originally collected by Fechser were very likely to have been selected for the forms with the strongest and most spectacular spination. If we follow the point of view of M. Meregalli & Tomáš Kulhánek, only the taxon Gymnocalycium catamarcenseSN|22552]]SN|22552]] f. belense H. Till and W. Till, here described, can claim synonymy with Gymnocalycium pugionacanthumSN|22551]]SN|22551]]. It is distinguished from other forms of Gymnocalycium catamarcenseSN|22552]]SN|22552]] by rounded, weakly oval, rounded areoles with very thick dark grey to black spines, 30 mm long at first dark grey to black, but afterwards bleaching ash-grey, and a stem that becomes columnar with age.
Subspecies, varieties, forms and cultivars of plants belonging to the Gymnocalycium pugionacanthum group
Bibliography: Major references and further lectures
1) M. Meregalli & Tomáš Kulhánek in: Schütziana 6(3): 2015
2) Gymnocalycium catamarcense ssp. catamarcense f. belense in Gymnocalycium galerie retrieved from http://www.gymnocalycium.fr/gymnocalycium-catamarcense/gymnocalycium-catamarcense-fma-belense/ 11 March 2017.
Cultivation and Propagation: Gymnocalycium catamarcenseSN|22552]]SN|22552]] f. belense is a summer grower species that is easy to cultivate.
Growth rate: It is a relatively slowly growing but easily flowering species.
Soils: It likes very porous standard cactus mix soil. Prefer a low pH compost, avoid substrata rich in limestone; otherwise growth will stop altogether.
Repotting: This plant needs plenty of space for its roots, repotting should be done every other year or when the it has outgrown its pot. Use pot with good drainage.
Watering: Needs moderate to copious waterings in summer, but do not overwater (Rot prone), keep dry in winter at a minimum temperature of 0°C.
Fertilization: Feed with a high potassium fertilizer in summer.
Hardiness: Reputedly resistant to frost if kept on the dry side prior to, and during, cold weather (hardy to -5 C ° C, or less for short periods).
Exposition: The plant tolerates extremely bright situations but enjoys filtered sunlight or afternoon shade, inside it needs bright light, and some direct sun. Tends to bronze in strong light, which encourages flowering and heavy spine production, but is likely to suffer from sun scorch or stunted growth if over exposed to direct sunlight during the hottest part of the day in summer. In full sun turns an uneven brownish red colour.
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 or outdoor in a rockery.
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: Red spiders may be effectively rubbed up by watering the plants from above.
- Mealy bugs: Mealy bugs occasionally 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: This species is particularly easy and accommodating, seldom suffer of cryptogamic diseases. Rot it is only a minor problem with gymnocalyciums if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much.
Propagation: Direct sow after last frost. Seeds germinate in 7-14 days at 21-27° C in spring, remove gradually the glass cover as soon the plants will be well rooted (ca 1-2 weeks) and keep ventilated, no full sun for young plants!
Gymnocalycium catamarcense f. belense H.Till & W.Till: has rounded, weakly oval areole with very thick spines, 30 mm long at first dark grey to black bleaching ash-grey. Distribution: Belén to Hualfin, Catamarca, Argentina.
