Origin and Habitat: This species occurs in Salta and Jujuy (Argentina) and Chuquisaca, Potosí and Tarija (Bolivia).
Altitudes: 2500 to 3900 meters above sea level.
Habitat: This cactus grows on rocky outcrops in puna grasslands, and sometimes in prepuna shrublands.

• Rebutia ritteri (Wessner) Buining & Donald
• Aylostera ritteri (Wessner) Mosti & Papini
• Digitorebutia brachyantha var. ritteri (Wessner) Donald
• Digitorebutia ritteri (Wessner) Buining
• Lobivia atrovirens var. ritteri (Wessner) Rausch
• Lobivia ritteri Wessner
• Mediolobivia euanthema var. ritteri (Wessner) Donald
• Mediolobivia ritteri (Wessner) Krainz

• Rebutia ritteri (Wessner) Buining & Donald
• Aylostera ritteri (Wessner) Mosti & Papini
• Digitorebutia brachyantha var. ritteri (Wessner) Donald
• Digitorebutia ritteri (Wessner) Buining
• Lobivia atrovirens var. ritteri (Wessner) Rausch
• Lobivia ritteri Wessner
• Mediolobivia euanthema var. ritteri (Wessner) Donald
• Mediolobivia ritteri (Wessner) Krainz
• Rebutia brunescens Rausch
• Aylostera brunescens (Rausch) Mosti & Papini
• Mediolobivia atrovirens var. brunescens hort.
• Mediolobivia brunescens hort. sensu Rausch
• Rebutia raulii Rausch
• Aylostera raulii (Rausch) Mosti & Papini
• Digitorebutia raulii (Rausch) Rausch
• Lobivia atrovirens var. raulii (Rausch) Rausch
• Rebutia ritteri var. pilifera (Frič) Buining & Donald
• Mediolobivia ritteri var. pilifera Backeb.

Description: Rebutia ritteriSN|25492]]SN|25492]] is an attractive dwarf cactus covered with characteristic with short spines and light green tubercles barely covering the body. It is a free-flowering species with fiery vermilion blooms. It is quite variable and has received numerous unnecessary names of no botanical value, representing no more than local phenotypes.
Habit: Plants forming clusters.
Stems: Roundish to slightly elongated, depressed at the top, grey-green, to 5 cm high and 3,5 cm in diameter covered by distinctive conical tubercles with hexagonal bases similar to a Mammillaria, that are easy to see through the small spines.
Ribs: Up to 18, forming distinct tubercles.
Areoles: Rather large, elliptical, brownish-tomentose.
Spines: 8-10, erect, fine, needle-like, all more or less similar, whitish grey with dark tips and bases, to 1 cm long.
Flowers: Flowers produced halfway up the stems, curving upward,flame coloured to crimson, throats reddish violet, to 4 cm long and 4,5 cm in diameter. Tube narrow.
Blooming season: Flowers all tend to come in one late Spring rush, rather than spread over the Summer, and remain open for up to six days.
Fruits: Tiny, spherical, berrylike, brownish to olive green.

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
3) Edward F. Anderson “The Cactus Family” Timber Press, 2001
4) Anderson E. F.: "The Cactus Family" Timber Press, Portland, Oregon, 2001
5) Ritter Fr.: "Kakteen in Südamerika" Spangenberg, 1980
6) Lowry, M. 2013. Rebutia ritteri. In: IUCN 2013."IUCN Red List of Threatened Species." Version 2013.1. <www.iucnredlist.org>. Downloaded on 15 October 2013.