Kroenleinia grusonii

Kroenleinia grusonii, commonly called mother-in-law's seat, golden barrel biznaga, golden ball , golden barrel, or hedgehog cactus, is a species belonging to the Cactaceae family. The monotypic genus to which it belongs, Kroenleinia, together with its relative genera Echinocactus and Ferocactus, are commonly known as barrel cactus.

It is endemic to central Mexico, from Tamaulipas to the State of Hidalgo, and despite being one of the most popular cacti in cultivation, it is considered rare and is listed as an endangered species in its wild habitat.

Description

Cactus with a more or less spherical globular shape. Generally solitary, although basal shoots may sprout from adult specimens. In the wild, it can measure more than 1 m in height, but since it is quite slow growing it can take many years, which is not a problem, given the longevity of this species, more than 100 years. The duration of one generation is estimated at 10 years.

Bright green, with a flattened apex and yellow wool. It has between 21 and 37 rectilinear ribs, prominent and thin, which cannot be seen in the youngest specimens, since they are divided into conical tubercles. The areoles are yellow woolly when the plant is young, then whitish and finally greyish. They are large and are 1 or 2 cm apart from each other. The radial spines are arranged in numbers between 8 and 10, and measure more than 3 cm in length. The central ones, between 3 and 5, measure about 5 cm; They are strong, striated and straight, although the central ones may be slightly curved downwards.

The flowers appear in the upper areoles of adult specimens in summer. They arise between wooliness and last 3 days. They measure between 4 and 7 cm in length and 5 cm in diameter. The external petals are yellowish on the inside and brown on the outside. The internal ones are yellowish and shiny.

Cultivation and uses

This species is easily propagated by seeds, which germinate in 5 or 7 days, with the plants reaching 10 cm in diameter after the first or second year of sowing. The plant requires a soft, well-drained substrate. Although younger specimens appreciate a little semi-shade, adult specimens should be placed in full sun, as they need direct sunlight and a minimum average temperature in winter of 15 °C. Most Kroenleinia tolerate cold well, often down to -7°C as long as they are healthy plants and dry soil conditions are respected. It is advisable to fertilize it from spring to summer and place it in a cactus substrate with a large part of coarse sand to facilitate drainage. Frequent watering in summer and almost none in winter; if the plant is an adult, watering is usually suspended completely at this time.

Diseases

It can be attacked by mealybugs and aphids.

Uses

Although it is a practically extinct species in its place of origin, it is cultivated throughout the world, as an indoor plant in a pot and as one of the most cultivated in landscape gardening.

Taxonomy

The genus was described by Joël Lodé and published in Cactus-Aventures International 102: 25–29, in 2014.

The single species was initially described as Echinocactus grusonii by Heinrich Hildmann and published in Monatsschrift für Kakteenkunde 1: 4, in 1891, it is currently both a synonym and a basonym of this;

Etymology

Kroenleinia: generic name given in honor of the Monegasque Marcel Kroenlein (1928 – 1994), director of the Exotic Garden of Monaco (1969 – 1993).

grusonii: epithet given in honor of the German engineer, inventor, businessman and plant collector Hermann Gruson (1821 – 1895).

Gallery

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  In their habitat

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  View of the plant

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  Small spine plant

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  Pencil and spines

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  Flower

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  Fruit

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  Seeds

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  Detail of the thorns