  
 
Ferocactus is a genus of large barrel-shaped cacti, mostly with large spines and small flowers. There are about 30 species included in the genus. This member of the Cactaceae family is found in the south-western United States and north-western Mexico. The young specimens are columnar but as they grow older ribs form and they take on a barrel form. Most of the species are solitary but some, such as Ferocactus robustus and Ferocactus glaucescens, form clumps. The flowers are pink, yellow, red or purple depending on the species, and the petals sometimes have a stripe of a darker colour. They are desert dwellers and can cope with some frost and intense heat. The typical habitat is hot and very arid, and the plants have adapted to exploit water movement to concentrate their biomass in areas where water is likely to be present.   
  Like Sclerocactus, Ferocactus typically grow in areas where water flows irregularly or depressions where water can accumulate for short periods of time. They are most often found growing along arroyos (washes) where their seeds have been subjected to scarification due to water movement, but they oddly also tend to grow along ridges in spots where depressions have formed and can hold water for some period of time. Ferocactus have very shallow root systems and are easily uprooted during flash floods.
 The "fishhook" spines and the armoured web of spines enclosing the cactus body in many species of this genus are adaptations which allow the plant to move to more favourable locations. In cultivation Ferocactus require full sun, little water, and good drainage. They are popular as indoor houseplants providing they receive a few hours of sunlight a day. They are well suited for growing in pots and rockeries. Propagation is usually from seeds as most do not produce off-sets.
Ferocactus glaucescens commonly known as Blue Barrel Cactus is native to the limestone hills of Hidalgo, Mexico. This Ferocactus stands out from the other species. The spines are relatively neatly distributed, and the unusual-looking white fruits are unique. Though it can reach over 45 cm in diameter, it will nonetheless flower perfectly well in a 20 cm pot. It can be a very neat, compact and attractive addition to any collection. 
  
 
  
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