Angiosperms (Flowering Plants) • Earth.com

Mammillaria grusonii

(Mammillaria grusonii)

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Description

Mammillaria grusonii is a cactus in the genus Mammillaria of the family Cactaceae. The epithet grusonii honors the inventor, scientist, industrialist and cacti collector Hermann Gruson of Magdeburg. Mammillaria grusonii usually grows singly. This cactus is spherical to thick cylindrical, bright green, with a diameter of about 25 centimetres (9.8 in). The tubercles are four-angled and contain latex. The axillae are initially woolly, later naked. The spines are straight, reddish and becomes white with age. The two central spines are 0.4 to 0.6 centimeters long, while the 12 to 14 radial spines are 0.6 to 0.8 centimeters long. The pale yellow, bell-shaped flowers are up to 2.5 centimeters long and have an equal diameter. The fruits are bright scarlet and contain brown seeds. This species can be found in Mexico (in the states of Coahuila and Durango), at an altitude of 800–1,850 metres (2,620–6,070 ft) above sea level. Mammillaria is one of the largest genera in the cactus family (Cactaceae), with currently 200 known species and varieties recognized. Most of the mammillaria are native to Mexico, but some come from the southwest United States, the Caribbean, Colombia, Venezuela, Guatemala and Honduras. The common name "pincushion cactus" refers to this and the closely related genus Escobaria. The first species was described by Carl Linnaeus as Cactus mammillaris in 1753, deriving its name from Latin mammilla, "nipple", referring to the tubercles that are among the distinctive features of the genus. Numerous species are commonly known as globe cactus, nipple cactus, birthday cake cactus, fishhook cactus or pincushion cactus though such terms may also be used for related taxa, particularly Escobaria. The distinctive feature of the genus is the possession of an areole split into two clearly separated parts, one occurring at the apex of the tubercle, the other at its base. The apex part is spine bearing, and the base part is always spineless, but usually bears some bristles or wool. The base part of the areole bears the flowers and fruits, and is a branching point. The apex part of the areole does not carry flowers, but in certain conditions can function as a branching point as well. The plants are usually small, globose to elongated, the stems from 1 cm to 20 cm in diameter and from 1 cm to 40 cm tall, clearly tuberculate, solitary to clumping forming mounds of up to 100 heads and with radial symmetry.

Taxonomic tree:

Domain:
Kingdom: Plantae
Phylum:
Class: Magnoliopsida
Order:Caryophyllales
Family:Cactaceae
Genus:Mammillaria
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