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Accepted Scientific Name: Rebutia mentosa (F.Ritter) Donald
Bradleya 5: 93. 1987
Origin and Habitat: Sulcorebutia flavissima occours at the Orkho Abuelo foot and in the adjacent areas, between Aiquile and Mizque, Cochabamba department, Bolivia
Altitude range: 2400-2800(3250?) metres above sea level.
Habitat and ecology: Yellow spined specimens (S. flavissima) occurs along with dark spined individuals (S. mentosa) in the whole area around Aiquile. Nowhere homogeneous stands of Sulcorebutia flavissima had been found, but yellow and dark plants grow intermingled close one to each other, and are part of the same polymorphic population.
Rebutia mentosa (F.Ritter) Donald
Bradleya 5: 93. 1987
- Rebutia mentosa (F.Ritter) Donald
- Sulcorebutia albissima (F.H.Brandt) Pilbeam
- Sulcorebutia albata hort., Kníže
- Sulcorebutia albida hort., Kníže
- Weingartia albissima F.H.Brandt
- Weingartia mentosa var. albissima (F.H.Brandt) Hentzschel & K.Augustin
- Sulcorebutia albissima f. pectinifera hort.
- Sulcorebutia cupreata Kníže, n.n.
- Sulcorebutia х erinacea Slaba & Šorma non F.H.Brandt
- Sulcorebutia flavida (F.H.Brandt) Pilbeam
- Weingartia flavida F.H.Brandt
- Sulcorebutia flavissima Rausch
- Sulcorebutia formosa (F.H.Brandt) Pilbeam
- Weingartia formosa F.H.Brandt
- Sulcorebutia mairanana hort.
- Sulcorebutia santiaginiensis Rausch
- Sulcorebutia mentosa subs. santiaginiensis
- Sulcorebutia purpurea var. santiaginiensis....
- Sulcorebutia purpurea subs. santiaginiensis (Rausch) Slaba
- Sulcorebutia swobodae K.Augustin
- Weingartia mentosa var. swobodae (K.Augustin) Hentzschel & K.Augustin
- Sulcorebutia torotorensis (Cárdenas) F.H.Brandt
- Sulcorebutia unguispina Rausch
Rebutia mentosa subs. purpurea (Donald & A.B.Lau) Donald ex D.R.Hunt
Cactaceae Consensus Init. 3: 6. 1997
- Rebutia mentosa subs. purpurea (Donald & A.B.Lau) Donald ex D.R.Hunt
Description: Sulcorebutia flavissima is generally included within (as a synonym of) Rebutia mentosa, suggesting that there is not really a fundamental difference between the two. The name "flavissima", meaning "most yellow", refers to the yellow colour of spines. The overall yellow appearance helps distinguish this plant from other morphological forms of Rebutia mentosa. It is a clear form of Rebutia mentosa. Plants of Rebutia mentosa may show different colours of spines, as well as flowers. Often plants with lighter spines tend to have a lighter skin colouration and sometimes lighter flowers too.
Stem: Single, flat hemispherical 25 mm tall and 60 mm wide, in cultivation occasionally reaching 60-70 mm in width and forming a tuft. Epidermis bright green. Ribs up to 18, spiralling.
Areole: Elongate about 8 mm long with a creamy white wool.
Radial spines: About 24, up to 20 mm long, bent radially towards the apex, bright yellow.
Central spines: 2-5, about 20 mm long, thicker than the radials, protruding at the top of the areoles, bright yellow.
Flowers: 35 mm long, 40-50 mm wide. Perianth segments, often with a fine tip, dark to pale violet-red, with lighter medium strips, sometimes almost wholly white. Ovary and tube pink with darker scales. Throat, stamens, style and stigma white.
Fruit: Sherical, 7-10 mm wide, reddish brown with lighter scales.
Seed: About 1.2 mm long and 0.8 mm wide, testa matt black, hilum rounded, dark.
Bibliography: Major references and further lectures
1) Otakar Šída “Sulcorebutia mentosa Ritter var. flavissima (Rausch) Šída comb. et stat. Nov.” Atlasu kaktus? 2004 Retrieved 08 April 2016 from <http://www.cact.cz/noviny/2004/05/Sulcorebutia_mentosa_var_flavissima.htm>
2) Augustin K., Gertel W., Hentzchel G., “Sulcorebutia, Kakteenzwerge der bolivianischen Anden”, p. 110, 2000
3) Backeberg C. et Haage W., “Das Kakteenlexikon”, p. 506, 1977
4) Brinkmann K.-H., “Die Gattung Sulcorebutia”, p. 31, 1976
5) Hájek F., “Sulcorebutia mentosa Ritter”, Atlas kaktus? 1986, t.41, 1987
6) Klikar J., “Sulcorebutia flavissima Rausch”, Kaktusy 24:4, 1988
7) Lindner P., “P?ehled rodu Sulcorebutia Backeberg emend. Brederoo et Donald”, Aztekia (mimo?ádné ?íslo), p. 77, 1982
8) Odehnal J., Slaba R., “Rod Sulcorebutia – poznámky pod ?arou”, Kaktusy 37 / speciál 2, 2001
9) Pilbeam J., “Sulcorebutia and Weingartia, A Collector's Guide”, p. 49, 1985
Cultivation and Propagation: Sulcorebutias are summer grower species easy to cultivate, more cold tolerant than most. These mountainous plants have thick taproots and are susceptible to overwatering. They requires also an appropriate air circulation and are sometime grafted to avoid root problems.
Growth rate: It is a relatively rapidly growing and easily flowering species. It's a heavy clumper and produces a nice patch over time.
Soils: It likes very coarse mineral cactus mix soil, but can become too elongated if compost is too rich.
Repotting: Use pot with good drainage.
Watering: Water regularly from Spring to Autumn, but do not overwater(Rot prone), it must be strictly kept dry throughout the winter quiescent period since it is very sensitive to any moisture excesseskeep dry in winter.
Fertilization: Feed with a high potassium fertilizer in summer.
Hardiness: They need to be kept in a cool place during winter rest and are somewhat resistant to frost if kept on the dry side prior to, and during, cold weather (due to the altitude they are hardy to -7 C ° C, or less for short periods). The cold is important for the flowers, as well as for their health. Without this cool winter period, they normally won't get any buds.
Exposition: Requires full sun or light shade and careful watering to keep plant compact with strong coloured spines. Tends to bronze in strong light, which encourages flowering and heavy spine production. Light shadow my be useful in the hottest summer days.
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 sopiders may be effectively rubbed up by watering the infested 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.
- Sciara Flies: Sciara flies are one of the major problems for seedlings. It is a good practice to mulch your seedlings with a layer of grit, which will strongly discourage the flies.
- Scales: Scales are rarely a problem.
It is wise to treat your whole collection with a systemic insecticide twice a year in spring and autumn.
- Rot: Rot 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. To prevent rottenness it is also advisable to surround its root neck by very rough sand or grit, this help a fast water drainage.
Propagation: Seed, cutting, grafting. 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!
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