Origin and Habitat: Otuzco, Department of La Libertad, Peru
Altitude: 2500-3600 metres above sea level.

• Matucana ritteri Buining
• Borzicactus ritteri (Buining) Donald
• Submatucana ritteri (Buining) Backeb.

Description: Matucana ritteriSN|3774]]SN|6063]] (Formerly known as SubSN'>6064' alt='6089'>Matucana ritteri#SN#6063'>Sub[[Matucana ritteriSN' style='border:none;'>) is a low-growing, perennial stem succulent vaguely reminiscent of Matucana madisoniorumSN|6017]]SN|2238]]. This plant is a possible relative of Matucana aurantiaca but differing in having fewer spines (8-15) and more ribs (12-22).
Habit: Plants usually solitary or forming just a few offsets around the base.
Stem: Flattened globose to somewhat elongated especially in cultivation, glossy dark green, 3-5 cm high, 5-10 cm in diameter.
Root: Weak napiforme.
Ribs: 12-22, dull upward, blunt up to 1 cm broad at the base.
Areoles: Oval, 5-10 mm in length 3-6 mm wide, pale grey and 1-2 cm apart.
Spines: 8(-9)-15(-19), at first brownish, reddish black or black, becoming grey, straight to slightly curved.
Central spines: 1-2(-5), 20-40 mm long.
Radial spines: 7-10(-14), 10-30 mm long.
Flowers: Zigomorphyc, oblique, relatively narrow-tubed, vermilion-carmine with violet petals edge, 7-9 cm long, 4,5-5 cm in diameter. Floral tube 4 mm thick, reddish and covered with white flakes. Filaments purple white at the base. Style purple, with 5-6 reddish green stigma lobes about 2 mm in length.
Blooming season: Late spring to early summer.
Fruits: Shiny red and green, covered with scales and woolly hairs, 10-15 mm in diameter.
Seeds: Black 1,2 mm long and 0,7 mm thick.
Remarks: Matucana ritteriSN|5976]]SN|6063]] along with the related Matucana formosaSN|6063]]SN|5976]], Matucana inertexta, Matucana huagalensisSN|2238]]SN|6017]] and Matucana weberbaueriSN|6063]]SN|6089]] is part of the Matucana aurantiacaSN|6063]]SN|3774]] group.

Bibliography: Major references and further lectures
1) Friedrich Ritter “Kakteen in Südamerika Ergebnisse meiner 20jährigen Feldforschungen: Volume 4: Peru” 1981
2) 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) Hans Hecht “Cacti & succulents” Sterling Pub. Co., 1997

Cultivation and Propagation: It is a summer-growing species of relatively easy cultivation. This plant is adapted to dry soils and is quite susceptible to over-watering if kept in a non ventilated place.
Growth rate: Matucanas grow slowly in their natural habitats, but in greenhouses they grow more quickly.
Soil: Grow it in a rich, open, sandy-gritty cactus compost. It needs good drainage and a deep pot to accommodate its tap root.
Repotting: Repot in the spring when the roots become cramped. Generally, these plants should be re-potted every other year, in order to provide fresh soil. However, this doesn't necessarily mean they'll need larger containers. After repotting, do not water for a week or more.
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. Direct sun is also beneficial in order to get a good spine colouration.
Watering: Water sparingly 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 plants kept perfectly dry but may to survive a light frost.
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). 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.