Origin and Habitat: Oroya borchersiiSN|1500]]SN|1500]] is endemic to Peru’s Áncash region (Cordillera Blanca and Cordillera Negra), northern Peru, where it grows in dispersed areas in the Santa river catchment. Oroya borchersiiSN|1500]]SN|1500]] has a wide range and is very common.
Altitude range: 3,900 to 4,300 metres above sea level
Habitat and ecology: This cactus grows in the arid puna in on hard rocky soils and on exposed sloping land with grass, red earth and moss. It is currently not exposed to any major threat, although the potential impact of mining activities should be monitored. Tephrocactus floccosusSN'>4149]SN|4107]] and Tephrocactus hirschiiSN|4107]]SN|4149]]. Prof. Rauh of the Botanical faculty of Heidelberg notes that during one of his study trips through Peru he made measurements of ground surface temperatures at a height of 4225m in the Cordillera Negra at the growing place of Oroya borchersiiSN|1500]]SN|1500]]. These temperatures are clearly of prime importance for plant growth. Around midnight the the temperature was -3°C, at 7 a.m. the mercury dropped to -7°C and at about 11 a.m. it had climbed up to 38°C under the influence of the radiant sunshine. The plants are thus subject to a temperature range of 45°C; it is true that this is in the dry season which is also the coldest. The dry season falls in winter (April-September) during which the grass leaves wither completely and the whole Puna takes on a yellowish brown colour. During the summer season (October-April) much rain falls on these heights and the temperature is higher. This is the growing season on the puna. The seeds then germinate and everything becomes green.[10] [11] [12].

• Oroya borchersii (Boed.) Backeb.
• Echinocactus borchersii Boed.

Description: Oroya borchersiiSN|1494]]SN|1500]] is a solitary or clustering, globular cactus about 20 cm in diameter which is completely covered with thin yellow spines. It is one of the most beautiful species of the genus, and can be described without exaggeration as a jewel of the Peruvian flora. The plants has many ribs, elongate areoles, and pectinately arranged spines. Notable with O. borchersii is the central inflorescence. The small yellow-green or yellow flowers are rarely produced in cultivation.
Derivation of specific name: This species has been named in honour of Dr. Ph. Borchers, leader of a German-Austrian expedition to the Peruvian Andes. They are variable with respect to spination, stem shape, and flower color, probably in part the effects of the intense solar radiation and high elevation.
Stems: Globose to short cylindrical 12-32 cm tall, 15-22 cm in diameter. As younger plants O. borchersii set close pressed against the ground and are depressed globular. As the plants become older, they exhibit a tendency to extend in height, whereby the bottom becomes more or less corky.
Ribs: Numerous, 12-30. The ribs are completely hidden behind the spines.
Areoles: Elongate ,brown
Spines: Fine, yellowish to reddish brown, pectinately arranged barely differentiated as centrals and radial 2-2.5 cm long. Radial spines 25-30, thin and needle-like to bristly. Central spines 1-3. The oldest spines at the base of the stem become grey to black with age.
Flowers: The flowers appear packed closely together at the centre of the globular plant body, they are wholly yellow green to yellow, up to 2 cm long and 1.5 cm in diameter, funnelform to bell shaped, with a very short floral tube and only partially opening.
Blooming season. Typical in habitat Oroya borchersiiSN|1500]]SN|1500]] flowers in the so-called winter period which at these altitudes is dry and sunny with extremely low night time temperatures. The seeds would then germinate in the subsequent moist summer season. In cultivation it tend to flower during the day in summer, but infrequently.
Fruits: Club-shaped yellowish-green and up to 2.5 cm long.
Taxonomy: Their similar appearance and their relationship with Oroya subocculta (now generally included within as a synonym of Oroya peruvianaSN|1516]]SN|1494]]) is unmistakable, mainly with the varieties Oroya subocculta var. laxiareolataSN|1499]]SN|1499]] (Rauh & Backeb.) Slaba and Oroya suboccultaSN|1494]]SN|1516]] var. pluricentralis (Backeb.) Slaba. The oroyas occur in two distinct areas of the Peruvian Andes: the region in the north near Huaraz with O. borchersii, and the other, larger region, extending from Oroya to Cuzco, with O. peruviana. Probably Oroya borchersiiSN|1500]]SN|1500]] is just a northern variant of Oroya peruvianaSN|1500]]SN|1494]]. [1] [2] [3] [4] [8] [12] [13].

Bibliography: Major references and further lectures
1) British Cactus & Succulent Journal Cactus & Succulent Society, 1999
2) The Cactus and Succulent Journal of Great Britain, Volumes 39-40 Cactus and Succulent Society of Great Britain, 1977
3) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
4) 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
5) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
6) Ostalaza, C. & Cáceres, F. 2013. Oroya borchersii. The IUCN Red List of Threatened Species 2013: e.T152207A609849. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T152207A609849.en. Downloaded on 06 April 2017.
7) Arakaki, M., Ostolaza, C., Cáceres, F. and Roque, J. 2006. “Cactaceae endémicas del Perú.” Revista Peruana de Biología 13(2): 193s-291s.
8) Urs Eggli, Leonard E. Newton “Etymological Dictionary of Succulent Plant Names” Springer Science & Business Media, 29 June 2013
9) Brako, L. & J. L. Zarucchi. (eds.) 1993. “Catalogue of the Flowering Plants and Gymnosperms of Peru.” Monogr. Syst. Bot. Missouri Bot. Gard. 45: i–xl, 1–1286.
10) Rauh, W. 1958. “Beitrag zur Kenntnis der peruanischen Kakteenvegetation.” Stizungsber. Heidelberger Akad. Wiss., Math.-Naturwiss. Kl. 1–542.
11) Ritter, F. 1981. “Kakteen in Südamerika.” Vol. IV. Peru 1239–1692. Friedrich Ritter Selbstverlag, Spangenberg.
12) F.Vandenbroeck. “The genus Ooroys” Succulenta 4.60.1980
13) “The Chileans '87” Volume 13 Number 45

Cultivation and Propagation: Oroya borchersiiSN|1500]]SN|1500]] is a summer grower species that is easy to cultivate. The major challenge is to get these plants not just to grow well, but to flower well. It is one of the most cold-tolerant South American species. It can grow outdoors and is hardy to -15° C or even less.
Growth rate: It is a relatively rapidly growing species that will make clumps given the best conditions.
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: Use pot with good drainage.
Watering: Needs moderate to copious waterings in summer, but do not overwater (Rot prone), keep dry in winter.
Fertilization: Feed with a high potassium fertilizer in summer.
Hardiness: Reputedly very resistant to frost if kept on the dry side prior to, and during, cold weather (hardy to -15 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.
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: Rot it 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.
Propagation: Division, 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! To make a cutting twist off a branch and permit it to dry out a couple of weeks, lay it on the soil and insert the stem end partially into the soil. Try to keep the cutting somewhat upright so that the roots are able to grow downward.