The genus Notocactus is a member of Buxbaum's tribe Notocactinae. This tribe consists of mostly globular genera (Eulychinia being the exception) of exclusively South American origin. These genera were further split into the following four sub-tribes.
From this we can see that Notocactus belongs to a group of short-columnar to globular and dwarf genera. There is a further "unofficial" division of this sub-tribe, according to the altitude distribution, into the so called "Pampas line" and "High mountain line".
The "Pampas line" consists of the two genera, Notocactus and Frailea, found at relatively low altitudes, below about 1000 m. The plants grow mostly on "islands" of low rocky hills found in grass lands and forests. The distribution for this group is very wide, covering Argentina, Paraguay, Uruguay, and Southern Brazil. Notocactus species are found mostly in Southern Brazil, especially Rio Grande do Sul, and Uruguay, with various species found in Paraguay and a few, notably forms of N. submammulosus, found in North Eastern Argentina.
The "High mountain line" consists of the other two genera, Parodia and Blossfeldia. These are found at altitudes ranging from 500 m to 4200 m. The plants grow mostly in the eastern mountains and foot hills of the Cordilleras of Argentina, Bolivia and Paraguay. (Blossfeldia only in Southern Bolivia and Northern Argentina.)
The current theory is there was originally an ancestor of these four genera which has divided into the mountainous branch of Parodia and Blossfeldia, and the lowland branch of Notocactus and Frailea.
There is very little crossover of these groups, with only species such as N. submammulosus, N. sessiliflorus and some members of the Paucispini coming into contact with species of Parodia.
This group of genera have had a confusing past, with Uebelmannia and what we now call Notocactus subgenus Brasiliparodia both originally being described as Parodia. In 1984 F. Brandt attempted to reduce the Eriocacti to a subgenus of Parodia, on account of perceived similarities of the seeds. This recombination was vigorously denied by many Notocactus enthusiasts, many of whom believe that the Eriocacti are in fact an older group of plants than both Notocactus and Parodia. Brandt also transferred the Brasilicacti to Parodia.
In the mid 80's there began a move, within the IOS, to try and tidy up the naming of genera of the Cactaceae. It was believed there were far too many generic names which had been established by people such as Kurt Backeberg and Friedrich Ritter. I think most of us believe at least some of these genera, based on some rather tenuous characteristics, are better reduced to sub-genera if not ignored entirely.
Over a period of discussion and consultation between some of the members of the IOS, the preliminary findings were published in Bradleya 4 :65-78, 1986. These findings had managed to reduce the number of "accepted" genera from an absurd high of over 200 to an almost equally absurd low of 86. During this process we seem to have lost such well known genera as Lobivia (subsumed into Echinopsis), Sulcorebutia and Weingartia (subsumed into Rebutia), Notocactus and Blossfeldia (subsumed into Parodia). Uebelmannia and Frailea were left as independent genera with notes stating that Uebelmannia should be regarded as Parodia. Frailea seems to have been left out because of the, possibly embarrassing, fact that the name Frailea is older than Parodia, which means that had Notocactus, Parodia, Uebelmannia, Blossfeldia and Frailea been amalgamated into a single genus then that genus would, according to the rules of the ICBN, have to be called Frailea !!
The second edition of the CITES Cactaceae Checklist gives a list of just over 100 accepted genera. We will have to wait until the publication of the new IOS cactus lexicon to see the official number.
So we come to the crunch. In 1989 N.P. Taylor published the recombination of the genus Notocactus into the genus Parodia in The European garden flora 3, Dicotyledons (part 1) : 257-265. This was an expected consequence of the moves by the IOS outlined above. What was not expected was the apparent lack of any detailed research. Which had resulted in a fairly large number of inaccuracies and errors. All of these mistakes could quite easily have been avoided had Taylor, etc. consulted any of the published literature such as Die Gattung Notocactus by Gerhardt Schäfer, KuaS, Succulenta and especially Internoto.
After the initial outcry this provoked, most of the mistakes were corrected by various authors in taxonomic publications such as " CITES Cactaceae Checklist" and "Cactaceae Consensus Initiatives" (issue 9 and beyond have been renamed "Cactaceae Systematics Initiatives"). However the current works still exclude the vast majority of Notocactus "names". This is either because a particular "name" was invalidly published or because the taxa is below the rank of subspecies. Most of the valid excluded taxa are treated as synonyms of their parent taxa.
|Species name as Parodia||As Notocactus||Synonyms|
|alacriportana Backeberg and Voll||alacriportanus|
ssp. brevihamata (W. Haage) Hofacker and P. J. Braun
ssp. buenekeri (Buining) Hofacker and P. J. Braun
ssp. catarinensis (F. Ritter) Hofacker and P. J. Braun
|allosiphon (Marchesi) N.P. Taylor||allosiphon|
|arnostiana (Lisal and Kolarik) Hofacker||arnostianus|
|buiningii (F. Buxbaum) N.P. Taylor||buiningii|
|carambeiensis (Buining and Brederoo) Hofacker||villa-velhensis|
|concinna (Monville) N.P. Taylor||concinnus||apricus|
ssp. agnetae (van Vliet) Hofacker
ssp. blaauwiana (van Vliet) Hofacker
|crassigibba (F. Ritter) N.P. Taylor||crassigibbus|
|curvispina (F. Ritter) D. Hunt||curvispinus||rubropedatus|
|erinacea (Haworth) N. P. Taylor||erinaceus||acuatus|
|erubescens (Osten) D. Hunt||erubescens||schlosseri|
|fusca (F. Ritter) Hofacker and P. J. Braun||fuscus|
|haselbergii (Rümpler) Brandt||haselbergii|
ssp. graessneri (Schumann) Hofacker and P. J. Braun
|herteri (Werdermann) N.P. Taylor||herteri||pseudoherteri|
|horstii (F. Ritter) N.P. Taylor||horstii||purpureus|
|langsdorfii (Lehmann) D. Hunt||langsdorfii||leprosorum|
|leninghausii (Schumann) Brandt||leninghausii|
|linkii (Lehmann) R. Kiesling||linkii||megapotamicus|
|magnifica (Ritter) Brandt||magnificus|
|mammulosa (Lemaire) N.P. Taylor||mammulosus||cristatoides|
ssp. brasiliensis (Havlicek) Hofacker
ssp. erythracantha (Schlosser and Brederoo) Hofacker
ssp. eugeniae (van Vliet) Hofacker
ssp. submammulosa (Lemaire) Hofacker
|meonacantha (Prestlé) Hofacker||meonacanthus|
|mueller-melchersii (Backeberg) N.P. Taylor||mueller-melchersii|
ssp. gutierrezii (Abraham) Hofacker
ssp. winkleri (van Vliet) Hofacker
|muricata (Otto ex Pfeiffer) Hofacker||muricatus||laetivirens|
|neoarechavaletae (Havlicek) D. Hunt||neoarechavaletae||maldonadensis|
|neohorstii (Theunissen) N.P. Taylor||neohorstii|
|nigrispina (Schumann) Brandt||nigrispinus|
|nothorauschii D. Hunt||rauschii||spinibarbis|
|ottonis (Lehmann) N. P. Taylor||ottonis||acutus|
ssp. horstii (F. Ritter) Hofacker
|oxycostata (Buining and Brederoo) Hofacker||oxycostatus||campestrensis|
ssp. gracilis (F. Ritter) Hofacker
|permutata (F. Ritter) Hofacker||permutatus|
|rechensis (Buining) Brandt||rechensis|
|rudibuenekeri (Abraham) Hofacker and P. J. Braun|
ssp. glomerata (Gerloff) Hofacker
|rutilans (Däniker and Krainz) N. P. Taylor||rutilans||roseiflorus|
ssp. veeniana (van Vliet) Hofacker
|schumanniana (Nicola) Brandt||schumannianus||ampliocostatus|
ssp. claviceps (F. Ritter) Hofacker
|scopa (Sprengel) N. P. Taylor||scopa||soldtianus|
ssp. marchesii (Abraham) Hofacker
ssp. neobuenekeri (F. Ritter) Hofacker and P. J. Braun
ssp. succinea (F. Ritter) Hofacker and P. J. Braun
|sellowii (Link and Otto) Hunt||sellowii||corynodes|
|stockingeri (Prestlé) Hofacker and P. J. Braun||stockingeri|
|tabularis (Cels ex Rümpler) D. Hunt||tabularis|
ssp. bommeljei (van Vliet) Hofacker
|tenuicylindrica (F. Ritter) D. Hunt||tenuicylindricus||minimus|
|turbinata (Arechavaleta) Hofacker||sellowii|
|turecekiana R. Kiesling||turecekianus|
|warasii (Ritter) Brandt||warasii|
|werdermanniana (Herter) N. P. Taylor||werdermannianus||ferrugineus|
|werneri (Buining) Hofacker||uebelmannianus||arachnites|
ssp. pleiocephala (Gerloff and Königs) Hofacker
My own view is there is still much work to be done on Notocactus, so we can understand the relationships of plants within the genus, before we can even begin to do any work on the relationships with other genera. Much is being done by Notocactus experts like Norbert Gerloff etc. and there is also DNA research being carried out on this group, with the aim of understanding the relationship between Notocactus, Parodia, Frailea, etc. and other Notocactinae. In fact recently (1999) work carried out by Reto Nyffler suggests that Frailea and Blossfeldia might not be part of sub-tribe Notocactinae at all.
There has already been a quite considerable amount of reorganization of the genus Notocactus by members of Internoto. This reorganization has lead to a reduction in the number of species by reducing many plants to varieties or forms of closely related species. This includes a reduction of many of the acutus series of the Paucispini. Much has also been done to clear up the structure of the subgenus Malacocarpus by Gerloff and Havlicek.