Origin and Habitat: Choros Valley north of la Serena and on the Hills near the El Tofo mine, region 04 Coquimbo, Chile

• Pyrrhocactus chorosensis F.Ritter
• Neochilenia chorosensis (F.Ritter) Backeb.
• Neoporteria chorosensis (F.Ritter) Donald & G.D.Rowley
• Neoporteria jussieui var. chorosensis (F.Ritter) A.E.Hoffm.

• Eriosyce heinrichiana (Backeb.) Katt.
• Horridocactus heinrichianus Backeb.
• Neoporteria curvispina var. heinrichiana (Backeb.) Donald & G.D.Rowley
• Neoporteria heinrichiana (Backeb.) Ferryman
• Pyrrhocactus heinrichianus (Backeb.) F.Ritter
• Neoporteria ritteri Donald & G.D.Rowley
• Pyrrhocactus chaniarensis F.Ritter
• Neoporteria jussieui var. chaniarensis (F.Ritter) A.E.Hoffm.
• Pyrrhocactus chorosensis F.Ritter
• Neochilenia chorosensis (F.Ritter) Backeb.
• Neoporteria chorosensis (F.Ritter) Donald & G.D.Rowley
• Neoporteria jussieui var. chorosensis (F.Ritter) A.E.Hoffm.
• Pyrrhocactus deherdtianus (Backeb.) Katt.
• Neochilenia deherdtiana Backeb.
• Neoporteria deherdtiana (Backeb.) Donald & G.D.Rowley
• Pyrrhocactus dimorphus F.Ritter
• Neochilenia dimorpha (F.Ritter) Backeb.
• Neoporteria dimorpha (F.Ritter) Donald & G.D.Rowley
• Neoporteria jussieui var. dimorpha (F.Ritter) A.E.Hoffm.
• Pyrrhocactus jussieui var. australis F.Ritter
• Pyrrhocactus jussieui var. spinosior F.Ritter
• Pyrrhocactus trapichensis F.Ritter
• Neochilenia trapichensis F.Ritter ex Backeb.
• Neoporteria jussieui var. trapichensis (F.Ritter) A.E.Hoffm.

• Eriosyce heinrichiana subs. intermedia (F.Ritter) Katt.
• Eriosyce heinrichiana var. intermedia (F.Ritter) Katt.
• Neochilenia setosiflora var. intermedia (F.Ritter) Backeb.
• Neoporteria setosiflora var. intermedia (F.Ritter) Donald & G.D.Rowley
• Pyrrhocactus setosiflorus var. intermedius F.Ritter

• Eriosyce heinrichiana var. setosiflora (F.Ritter) Katt.
• Eriosyce setosiflorus F.Ritter
• Neochilenia setosiflora (F.Ritter) Backeb.
• Neoporteria jussieui var. setosiflora (F.Ritter) A.E.Hoffm.
• Neoporteria setosiflora (F.Ritter) Donald & G.D.Rowley
• Pyrrhocactus setosiflorus F.Ritter

• Eriosyce heinrichiana var. simulans (F.Ritter) Katt.
• Eriosyce simulans (F.Ritter) Katt.
• Neochilenia simulans (F.Ritter) Backeb.
• Neoporteria simulans (F.Ritter) Donald & G.D.Rowley
• Pyrrhocactus simulans F.Ritter

Description: Eriosyce heinrichianaSN|2658]]SN|2658]] f. chorosensis|SN|16108]], also known by the old scientific name Pyrrhocactus chorosensisSN|16108]]SN|16108]], is a local or morphological form of the variable Eriosyce heinrichianaSN|2658]]SN|2658]] characterized by large open red flowers on a small dark body. Plant of this taxon are mostly spineless, but may be spiny too, and shows a certain degree of variability depending on origin. The otherwise similar features of “heinrichina” and “chorosensis”, namely size and form of stems, spines, flowers, fruit, etc., prove, that is impossible to differentiate between these taxa.
Habit: It is a tiny geophytic cactus rising barely above ground level, usually solitary or sometime branching.
Roots: Fibrous, arising from a large taproot which is narrowed into a necks where joining the stems.
Stem: 4-10 cm in diameter, hemispherical to spherical, flattened at the apex, but often elongate in cultivation, dull olive-green, brownish to blackish green often with purple sheen.
Ribs: 14-22, noticeably tubercled with pronounced chin-like protrusions.
Spines: Mostly absent, or (if present) 1 to 14, stiff, needle-like, variable from very short (less than 3 mm long) to 15 mm long (depending on individuals), straight or more or less curved and not easily distinguished as centrals or radials, creamy white, brown or black and darker at the tips, turning grey as they ages. Central spines (if present) 1-4, slightly stronger 3-15 mm long.
Flowers: Diurnal, 3-5 cm long and broad, closely packed apically from young areoles, funnel-form, the colour is reddish often with red/brownish midveins. Pericarpel and floral tube with bracts, wool and sparsely bristly.
Fruits: Oval, to 1,5 cm long, red, fleshy, thin walled and splitting open at maturity by basal pores.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
3) 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
4) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
5) Fred Kattermann “Eriosyce (Cactaceae): The Genus Revised and Amplified” David Hunt, 1994
6) Faundez, L., Guerrero, P., Saldivia, P. & Walter, H.E. 2013. Eriosyce heinrichiana. In: IUCN 2013. "IUCN Red List of Threatened Species." Version 2013.2. <www.iucnredlist.org>. Downloaded on 15 January 2014.

Cultivation and Propagation: Eriosyce heinrichianaSN|2658]]SN|2658]] is a slow growing but relatively easy to grow species, providing they are kept dry during autumn and winter and rot prone if kept in a non ventilated place.
Soils: Require a very fast mineral draining drying soil (70-80% grit and 20-30% of land soil). To prevent rottenness it is also advisable to surround its root neck by very rough sand or grit, this help a fast water drainage and an appropriate air circulation.
Watering Needs: Root prone it needs good drainage, waterings should regular in summer (do not overwater), to keep the plant compact and not become excessively elongated and unnatural in appearance. During the winter quiescent period, or when night temperatures remain below 10° C, it must be strictly kept dry since it is very sensitive to any moisture excesses.
Fertilization: During the beautiful season it’s good to enrich the soil using a fertilizer rich in potassium and phosphorous, but poor in nitrogen, because this chemical element doesn’t help the development of succulent plants, making them too soft and full of water.
Exposure: Requires strong sun exposure to develop good spinal growth (maximum brightness, sunlight accepted), but tolerate light shade. Some light shadow my be useful in the hottest summer days.
Frost Tolerance: Hardy to at least -5°C for a short period but cannot tolerate long standing freezing temperature, and for an healthy cultivation ensure a minimum temperature of 5° C. Assure a good ventilation. USDA Hardiness Zone 9b and 11.
Heat tolerance: Good heat tolerance, but in warmer climates it should be protected from excessive heat and too much sun sun in summer.
Maintenance: Repot in the spring, when its roots become cramped. Generally, it should be repotted every other year in order to provide fresh soil. After repotting, do not water for a week or more.
Propagation: Usually propagated from Seeds. (seldom produces offsets). Sow the seeds in spring in a well-aerated compost at a temperatures of 22-24°C . Stand the pots in water, moisten thoroughly and drain. Scatter and press lightly the seed onto the top of the compost. But do not cover the small seeds with compost. Secure a polythene bag around the pot or cover the container with glass or and place in a warm shaded place. If possible, germinate in a propagator. Some seedlings may appear within a week or 10 days others will take longer. At lower temperatures, germination usually takes considerably longer. Once germination has taken place, remove gradually the glass or plastic and move into a good light but not in direct sun. If the young plants are exposed to too much sun, or the compost dries out, they may stop growing and often turn red; once they stop, it is often difficult to persuade them to start growing again. Never let the pots dry out-but don't saturate them either. A sodden compost is as harmful as a dry one. The seedling growth is rapid. But the seedling are often grafted because the plants on their own roots (especially the bigger ones) are extremely prone to root rot. In fact the best and older specimens are the grafted ones.