Parodia leninghausii
Parodia leninghausii is a species of South American cactus commonly found as a houseplant. Common names include Lemon Ball cactus, Golden Ball cactus and Yellow Tower cactus. Botanist Karl Moritz Schumann named it after Wilhelm Lenninghaus (1845-1918), a native of North Rhine-Westphalia who, in the 1880s, left his hometown of Ennepetal and emigrated to Porto Alegre, Brazil, where he became Guillermo Lenninghaus, and collected cacti for the German grower Haage. "P. leninghausii" is native to the Rio Grande do Sul province in the south of Brazil. In those regions, winter nights are cold, with a light  freeze. These cacti survive in these conditions because they are quite dry at that time. "P. leninghausii" shows cactus species nomadism; it was successively included in genus "Pilocereus" K. Schumann 1895, "Malacocarpus" (K.Schumann) Britton & Rose 1922, "Notocactus" (K.Schumann) A.Berger 1929, "Eriocactus" (K.Schumann) Backeberg 1942, and finally ended up in "Parodia" (K. Schumann) F.H.Brandt 1982. Description. The species have many thin golden spines. The young plants are globular, then columnar up to 1m tall, 12 cm diameter and about 30 ribs. Old plants cluster from the base. Flowers are yellow, 5 cm diameter, at the top of the plants, but  only if adult (at least 20 cm tall) Sometimes, they present monstruous forms. There is a cultivar "albispina" with white spines. Cultivation. Like most cactuses, "Parodia leninghausii" needs well drained soil, sunny exposure, regular watering in summer and no watering in winter. In temperate climates, it may be placed outside in a warm sunny position during the summer months. In winter the plant tolerates frost at if kept totally dry. In cultivation, it is preferable to keep a cold temperature, but more than This plant has won the Royal Horticultural Society's Award of Garden Merit.