Publication: Eriosyce (Cactac.) gen. revis. & ampl. (Succ. Pl. Res., 1) 117 (1994)
Description
Eriosyce curvispina var. armata are usually solitary and flattened. (But nowadays the var. armata is considered none other han a synonym of Eriosyce curvispina, which is one of the most variable taxons in appearance. In fact, there are a number of varieties that are very different-looking, but not all the authorities recognize the different populations as segregate varieties.) The variety armata is very like aconcaguensis variety, but has flowers that are yellow with pink midstipes.
Stem: Dull, green, flattened, globular to shortly columnar, up to 15 cm tall, 8-20 cm in diameter.
Spines: Long, stiff. Young spines are greyish-brown to almost black with darker tips.
while older ones turn greyish.
Flowers: Flowers of Eriosyce armata are about 4 cm in diameter, and yellow with a red mid-vein.
Origin and Habitat
Metropolitana to Rancagua, Santiago, Chile.
Altitude: 600-800 metres above sea level.
Cultivation and Propagation
It is an extremely xerophytic, summer-growing, species, adapted to very dry soils. Despite its provenance it is not particularly difficult to cultivate, but quite susceptible to over-waterings and rot prone if kept in a non-ventilated place.
Growth rate: Slow-growing.
Soil: It requires a very fast draining drying open mineral, sandy-gritty cactus compostso. Provide a very good drainage.
Exposure: It is suited for sunny-brightly exposure, but can tolerate light shade. However it will do its best only with lots of sun and become stressed with inadequate light which could result in poor growth and unnatural shape. It has a good heat tolerance.
Watering: Water regularly in summer, but do not over-water and keep it completely dry during winter. Mature individuals easily rot and die especially after transplanting so be extremely cautious with watering. Keep dry in winter or when night temperatures remain below 10° C. Water it less than average if in bigger pots.
Fertilization: Feed them once during the growing season with a fertilizer specifically formulated for cactus and succulents (high potash fertilizer with a dilute low nitrogen), including all micro nutrients and trace elements diluted to ½ the strength recommended on the label. They thrive in poor soils and need a limited supplies of fertilizer to avoid the plants developing excess vegetation, which is easily attacked by fungal diseases.
Special need: It is suited for airy exposures. Provide very good ventilation. Nearly all problems occur as a result of overwatering and poor ventilation, especially when weather conditions are dull and cool or very humid. They must have very dry atmosphere.
Hardiness: It likes warmth (recommended minimum winter temperature 5° C), but Hardy to at least -5°C (it can probably tolerate freezing temperatures down to -10° C for brief periods) It has a good heat tolerance.
Pests & diseases: These cacti 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 misting the plants from above.
- Mealy bugs: Mealy bugs occasionally develop aerial into the new leaves and flowers with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.
- Scales, thrips and aphids: These insects are rarely a problem.
- Rot: Rot is only a minor problem if the plants are watered and “aired” correctly. If they are not, fungicides won’t help all that much.
Propagation: Usually propagated from seeds (seldom produces offsets) or graft. The seeds can be sown in pots of fine, well-drained sandy soil, any time during the spring when temperatures are warm. Cover the seeds with a fine layer of grit and water from below with a fungicide to prevent damping off. For the 1-2 weeks cover the pots with a sheet of glass/clear perspex to keep the humidity levels high. Remove the glass and replace it with light shade-cloth and mist once or twice a day for the next two weeks after which most seeds should have germinated. From then on mistings can be reduced to every second and then every third day as the little plants grow. The seedlings should not be disturbed until they are well rooted after which they can be planted separately in small pots. Sometimes it is grafted to avoid root rot problems as plants grafted on an hardy stock are easy to grow and no special skill is required.
Bibliography
Major references and further lectures
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Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
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Nathaniel Lord Britton, Joseph Nelson Rose “Cactaceae: Descriptions and Illustrations of Plants of the Cactus Family” vol. 4 The Carnegie Institution of Washington, Washington 1923
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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
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David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. “The New Cactus Lexicon” dh books, 2006
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