Notocactus is a genus of about 25 species of South-American cacti form low elevations of Argentina, Paraguay, Uruguay, and Southern Brazil. They are grown for their spine formations, as well as for their attractive flowers. The genus name comes from the Greek for "cactus from the south". It has now been merged with Parodia. Since the name Parodia was used before Notocactus, it has precedence and all the Notocactus became Parodia. Once separate genera but now included in Notocactus were Brasilicactus, Eriocactus, Malacocarpus, and Wigginsia. Closely related is Parodia, which comes from somewhat higher and dryer locales than Notocactus. They are often solitary, rarely offsetting, or producing stolons. All Notocactus are slow growing plants and make excellent house plants. They are globular to low columnar with characteristically depressed centers, usually many ribs, and usually many fine spines. They tend to be fairly short growing plants, but some species can reach 3 feet (90 cm), with cylindrical and spherical stems which are rarely branched. They are upright growing plants but may occasionally grow sideways with the top half looking as though it is wilting, this is less common that the upright growth and usually only occurs in old plants. The flowers usually last a week and tend to be yellow, in profusion, with red stigma lobes, and are borne on the upper "shoulders" of the plants in spring. Seed capsules retain the dried flower and are dry and papery when ripe. The seeds frequently fall next to the mother plant and germinate there. They bloom young, prolifically, and easily if not kept dry in the winter. They set seed readily. The habitat where Notocactus come from can become very cold during the winter nights; often it will fall to just above freezing without harming the plants as it is also very dry. When growing at home it is best to avoid any frost as you may loose the plant but during the winter the temperature can be as low as 2C without any harm so long as the compost is very dry. During the summer it is best to keep the plants outside where the temperature can rise to over 30C with no harm to the plant. If kept in a greenhouse you will need to watch the temperature as under glass it can rise dramatically particularly if the windows and vents remain closed. Notocactus cactus is best grown in a terracotta type pot which should have at least one drainage hole in the base and it should be unglazed. This type of pot allows good drainage and allows the compost (therefore the roots) to breath. The plants should be kept almost completely dry during the winter months, only water them to prevent the roots from completely drying out, once a month should be fine. From March onwards the plant will begin to grow and watering should be increased gradually until late May when the plant should be in full growth. As the compost is very free draining and the pot used is porous you can safely water this type of cactus at least once a week during the summer so long as the plant pot is allowed to drain and not sit in a tray of water. During hot weather you may need to water the plants once a day so long as the plant is actively growing. From late September watering should be reduced to force the plant to go in to a state of semi dormancy, by November you should be back in to the winter watering regime. Grow most species of Notocactus cacti in full sun during the summer and winter avoiding only the harshest summer sun, if kept too dark they may become overly lush and could be prone to rotting due to over watering, they will also be shy to produce flowers. If the compost is fresh then feeding may not be necessary at all, if the plant hasn't been repotted recently then half strength general purpose fertilizer can be used at watering time from May onwards once a month, but not during winter. Repotting should be done every other year or every three years, annual potting is not necessary. Remove the plant from its put by wrapping newspaper around the stem if it is very spiny. Carefully tap it out of the pot and remove the old compost to examine the roots, if any are damaged or showing signs of rotting they should be removed as close to the plant as possible. Re plant the cacti using the same mix of compost as it was originally in (fresh), and choose a pot just slightly wider then the width of the cactus. Do not be tempted to over pot as this will cause the unused compost to go stagnant and you may loose the plant.