Accepted Scientific Name: Gymnocalycium bodenbenderianum (Hosseus ex A.Berger) A.W.Hill
Kakteen (Berger) 1933 (A.Berger)
Gymnocalycium riojense Photo by: Alexander Arzberger
Origin and Habitat: Northern Argentina (La Rioja, San Juan and Catamarca).
Altitude range. 450-1600 metres above sea level.
Habitat and ecology:* This is one of a number of similar species that grow in flat ground or on gentle rocky slopes, often under bushes.
Synonyms:
See all synonyms of Gymnocalycium bodenbenderianum
Description: Gymnocalycium riojenseSN|14405]]SN|21407]] is a low growing cactus with a solitary brown body that will grow up to about 10 cm in diameter but it can take twenty years of culture to do so. However, the white-pink flowers are produced from the crown on much younger plants when only 5 cm in diameter. It is quite variable.
Taxonomy note. What is Gymnocalycium riojenseSN|21407]]SN|21407]]? Even the arch-splitter Backeberg abandoned G. riojense with the revealing comment that that G. riojense was probably Gymnocalycium bodenbenderianumSN|21407]]SN|14405]]. Today most authors accepts the point of view Backeberg that G. riojense and G. bodenbenderianum are synonymous and that G. bodenbenderianum has priority. Jörg Piltz considered G. riojense Frič ex H. Till & W. Till to be a more recent synonym of G. bodenbenderianum. The same view is held by D. Hunt and G. Charles. Hower the opinion that G. bodenbenderianum and G. riojense are separated species persist among the association of Gymnocalycium friends, the different spination as well as a separate distribution area are quoted as reasons. Much space is dedicated to this theory in various, partly extensive, papers (Till et Till 1991, Amerhauser 2009). It is suggested here that G. riojense grows in the Valle Fertil (Province San Juan), Chamical (Province La Rioja) and Casa de Piedra (Province Catamarca), whereas G. bodenbenderianum is found in the Sierra de Malanzan (Sierra de Argañaraz, Sierra de Abajo) and around Sierra de Ulapes.
Derivation of specific name: This member of the Cactaceae family was named after the Argentine province of La Rioja.
Stems: Flattened-globose, grey-green, olive green, greenish-brown to chocolate, 5-8 cm tall and 8-11 cm in diameter. Apex depressed, spineless, woolly.
Root: Napiform.
Ribs: 10-16, vertical, straight, rather acute, divided into conical tubercles with conical chins, separated by very apparent V-shaped transverse furrows.
Areoles: Oval, 3 × 4-5 mm, with yellowish felt, becoming greyish, then naked.
Spines: 3-5(-7) all radials, straight, overlapping, up to 15 mm long. Young spines light brown to blackish-brown, passing then to light grey with a dark point. Central spines absent.
Flowers: Apical up to 50 mm tall, and 40 mm in diameter. Pericarpel 15-20 mm long, olive-green to glaucous-green, the scales widely edged with white and with a pink point, passing gradually to the external tepals. The latter spatulate, white to rosy white, with an olive-green wide median band. Internal tepals lanceolate, white with a pink central line and carmine base. Throat dark carmine. Filaments pale green; anthers sulphur-yellow. Style greenish white with a pink base. Stigma yellowish white, with 9-12 lobes, between the primary and secondary stamens.
Subspecies, varieties, forms and cultivars of plants belonging to the Gymnocalycium bodenbenderianum group
Gymnocalycium bodenbenderianum (Hosseus ex A.Berger) A.W.Hill: Stem flattened with 11-14 low, rounded ribs, and 3-5 spines. Distribution: Cordoba and La Rioja.- Gymnocalycium bodenbenderianum subs. intertextum (Backeb. ex H.Till) H.Till: Stem flattened with 13-15 ribs, tubercles rounded and pointed. It has 5-7 spines. Distribution: northern Argentina.
- Gymnocalycium bodenbenderianum subs. intertextum var. moserianum Schuetz ex H.Till: Stem flattened globular up to 15 cm in diameter with ca. 10 ribs. Spines 3 to 5 all radial, up to 25 mm long, sometimes thin and curved. Distribution: Cordoba, Argentina.
- Gymnocalycium knollii Mereg.
- Gymnocalycium kozelskyanum Schütz
- Gymnocalycium pseudoragonesei Schuetz
- Gymnocalycium riojense Frič ex H.Till & W.Till: has 10-16, ribs. Spines: 3-5(-7) all radials up to 15 mm long. Distribution: Northern Argentina (La Rioja, San Juan and Catamarca).
- Gymnocalycium riojense subs. guasayanense (Strigl) H.Till
- Gymnocalycium riojense subs. paucispinum Backeb. ex H.Till & W.Till
- Gymnocalycium riojense subs. piltziorum Schütz ex H.Till & W.Till
- Gymnocalycium riojense var. platygonum Schütz ex H.Till & W.Till: Argentina, from north of Salinas Grandes, Catamarca, to East of Sierra Mazan, La Rioja.
- Gymnocalycium triacanthum Backeb.: has usually 3 radial spines, up to 10 millimetres long, sharp, stout, but not harmful, backward curved. Central spines: absent. Distribution:Catamarca, Córdoba, La Rioja, Argentina.
Bibliography: Major references and further lectures
1) J.G. Lambert “Cacti of Argentina” 2nd edition Revised and supplemented 1997 <https://www.cactuspro.com/biblio_fichiers/pdf/Lambert/LambertEN.pdf>
2) Graham Charles “Cacti and Succulents: An illustrated guide to the plants and their cultivation” Crowood, 30 April 2014
3) Amerhauser, H. (2009) “Gymnocalycium” 22(2): 857ff.
4) Berger, A. (1929) “Kakteen”.-Eugen Ulmer, Stuttgart.
5) Charles, G. (2009) “Gymnocalycium in habitat and culture”. - Eigenverlag - Ketton, Stamford.
6) Cocucci, A. E. (2003) C. C. Hosseus - “Notas Autobiograficas”. - Acad. Nac. Cient. Cord.
7) Papsch - “Comments on Gymnocalycium bodenbenderianum and Gymnocalycium riojense” Schütziana 5(2): pp. 3-14. 2014.
8) Crkal, K. (1983) “Lovec Kaktusů (A. V. Frič).” - Verlag Academia-Prag.
9) Frič, A. V. (1929) “Kakteenjäger”. - Eigenverlag-Prag.
10) Haage, F. A. (1928) “Kakteen-Preisverzeichnis” 1928. - Eigenverlag, Erfurt.
11) Hill, A. W. (1933) “Index Kewensis Plantarum Phanerogamrum”. - Clarendoniano - Oxford.
12) Hosseus, C. C. (1926) “Apuntes sobre las Cactáceas.” - Rev. Cent. Est. Farm. Cordoba II/6.
13) Hosseus, C. C. (1939) “Notas sobre Cactaceas Argentinas”. - Arch. Esc. Farm. Cordoba nr. 9.
14) Hunt, D. ed. (2006) “The New Cactus Lexicon”. - dh books - Milborne Port.
15) Kreuzinger, K. (1935) “Verzeichnis amerikanischer und and erer Sukkulenten mit Revision der Systematik der Kakteen”. - Verlag Kreuzinger-Eger.
16) Pazout, F., Valnicek, J. & Subik, R. (1960) “Kaktusy”. - Eigenverlag - Prag.
17) Till, H., Amerhauser, H. & Till, W. (2008) “Neuordnung der Gattung Gymnocalycium” Teil 2. - Gymnocalycium Sonderausgabe 2008 : 816.
18) Till. H. & Till, W. (1991) “Gymnocalycium riojense: Validierung, Beschreibung neuer Taxa und systematische Gruppierung nach morphologischen und arealmäßigen Kriterien.” Teil 1-3. - Gymnocalycium 2(4): 47 - 4(4): 58.
19) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
20) 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
Cultivation and Propagation: Gymnocalycium riojenseSN|21407]]SN|21407]] 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!
