It is clear that notocacti are currently out of fashion, a very different situation from back in the 1970s when many new species were being discovered in Brazil. For those who prefer a wider concept of genera (lumpers), this plant is a form of Notocactus oxycostatus (Buin. & Bred.) or Parodia oxycostata which is the name used in the New Cactus Lexicon. Ritter discovered N. acutus FR1377 with Leopoldo Horst in 1965, but it was not until his book Kakteen in Südamerika Vol. 1 was published in 1979 that he formally described it.
Fig. 1 N. acutus in cultivation
This taxon is related to the well-known Notocactus (Parodia) ottonis and needs similar treatment in cultivation. The soil must be acidic and kept moist during the growing period, ideally with rain water, when the plant will readily flower. An occasional light watering in winter will also help to keep the roots in good condition.
Fig. 2 N. acutus in habitat
In 2005, I saw it in nature near its type locality, Quevedos, Rio Grande do Sul, Brazil, GC794.01, where it shared its habitat with another N. ottonis relative, a glossy-bodied plant with smaller flowers, probably Notocactus linkii. The seeds I grew from this population made distinctive seedlings which flower reliably every year with lovely shiny yellow blossoms.
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