Accepted Scientific Name: Rebutia mentosa (F.Ritter) Donald
Bradleya 5: 93. 1987
Sulcorebutia albissima f. pectinifera Photo by: Valentino Vallicelli
SE122 Locality: Aiquile 7km to Misque, lower hill, 2380 m.
Origin and Habitat: Bolivia (Cochabamba) North West Aiquile 7 km to Mizque and adjacent areas.
Altitude: 2380 metres above sea level.
Synonyms:
See all synonyms of Rebutia mentosa
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Accepted name in llifle Database:Rebutia mentosa (F.Ritter) DonaldBradleya 5: 93. 1987Synonymy: 32
Accepted name in llifle Database:Rebutia mentosa subs. purpurea (Donald & A.B.Lau) Donald ex D.R.HuntCactaceae Consensus Init. 3: 6. 1997Synonymy: 4
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Description: Sulcorebutia albissimaSN|15253]]SN|15253]] f. pectinifera is an unnecessary catalog name used to indicate one of the innumerable local form of the very variable Rebutia mentosa with squat clustering stems and outstanding purple blooms. The var "pectinifera" has very tight white pectinate spines, and the spination of well-grown specimens is pleasing.
Habit: It was originally described as solitary, but often clusters in cultivation producing a nice patch over time.
Stems: Globular, flattened, or somewhat elongated-cylindrical in cultivation, up to 6 cm in diameter.
Radial spines: White to creamy, pectinately arranged, lying against the surface and interlacing, short needle-like.
Central spines: Usually absent.
Flowers: Several from the base, large intensely coloured glossy dark pink to purple-red.
Blooming season: Flowers are freely produced in spring (like all sulcorebutias) in this species.
Subspecies, varieties, forms and cultivars of plants belonging to the Rebutia mentosa group
- Rebutia mentosa (F.Ritter) Donald: (subsp. mentosa) has dark-brown or black spines; central spines 2-4. 5-8 mm long; radial spines 14-18 about 5 mm long.
- Rebutia mentosa subs. purpurea (Donald & A.B.Lau) Donald ex D.R.Hunt: has dark-green to purplish stems, with a few less radials (10-17 about 4-8 mm long), but a few more central spines (2-5, 8 -12 mm long). Spines whitish-yellow to reddish-brown. Distribution: Aiquile to Santiago, Cochabamba.
- Sulcorebutia albissima (F.H.Brandt) Pilbeam: Spines off-white, greyish, to light brown, pectinately arranged, lying against the surface, flowers glossy purple. Distribution: Cochabamba.
- Sulcorebutia albissima f. pectinifera hort.: has very tight white pectinate spines, and the spination of well-grown specimens is pleasing. Flowers bright purple. Distribution:Cochabamba (Aiquile to Mizque)
- Sulcorebutia cupreata Kníže, n.n.: has protruding white to yellowish spines. Flowers Red-purple. Distribution: Aiquile, Cochabamba, Bolivia.
- Sulcorebutia flavissima Rausch: has bright yellow spines and purple-pink flowers with paler throat. Distribution: Orkho Abuelo foot and in the adjacent areas, between Aiquile and Mizque.
- Sulcorebutia formosa (F.H.Brandt) Pilbeam
- Sulcorebutia mairanana hort.: This controversial plant probably correspond to Sulcorebutia albissima (a white spined form of Rebutia mentosa). Distribution: Mairana in Bolivia.
- Sulcorebutia santiaginiensis Rausch: very similar (if not the same) as Rebutia mentosa subs. purpurea but with somewhat weaker spines. Distribution: Aiquile to Santiago, Cochabamba.
- Sulcorebutia swobodae K.Augustin: has long soft, flexible spines, predominantly yellow but also brown to almost black. Distribution: Between Aiquile and Mizque, Cochabamba.
- Sulcorebutia torotorensis (Cárdenas) F.H.Brandt: it is very similar and referable (if not the same) to Rebutia mentosa subsp. purpurea. Distribution: Torotoro, Potosi, Bolivia.
- Sulcorebutia unguispina Rausch
Bibliography: Major references and further lectures
1) 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
2) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006 ISBN 0953813444, 9780953813445
3) Edward F. Anderson “The Cactus Family” Timber Press, 2001
4) John Pilbeam “Sulcorebutia and Weingartia: A Collector's Guide” Timber Press, 1985
5) Cyril Marsden, Herbert Spencer Jackson “Rebutia, Including Aylostera and Sulcorebutia” Macmillan, 1968
6) Terry Hewitt “Cacti” Lorenz Books, 01/Apr/1998
Sulcorebutia albissima f. pectinifera Photo by: Valentino Vallicelli Sulcorebutia albissima f. pectinifera Photo by: Valentino Vallicelli Sulcorebutia albissima f. pectinifera Photo by: Valentino Vallicelli Sulcorebutia albissima f. pectinifera Photo by: Valentino Vallicelli 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 that will make clumps given the best conditions.
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 excesses keep 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 spiders 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!