Biznaguita  (Mammillaria sanchez-mejoradae)

Classified as Critically Endangered (CR - B1ab(v)+2ab(v)) on the IUCN Red List 2002 (1), and listed on Appendix II of CITES (3).

This tiny cactus is extremely rare, and was only discovered in 1986 (2). The plant consists of a single small stem that is only around 25 cm across and is just visible above the ground. The stem is covered in many tiny swellings (known as tubercles), radiating numerous white spines that are tightly pressed against the cactus stem (2). White flowers emerge in a ring around the neck of the cactus; they open to 21 mm across revealing violet stripes in the middle of the petals and striking yellow stigmas. The fruit releases the majority of its seeds when the plant dies, having previously been sunken into the stem of the cactus (2).

Endemic to Mexico and known only from a single location in central Nuevo León (2).

The single location comprises a limestone outcrop at 1,900 - 2,000 metres above sea level (2).

Little is known about this recently discovered cactus.

This highly attractive and unusual cactus is extremely popular with collectors and the location of the single population is well known (1). It is estimated that the number of Biznaguitas in the wild has declined by as much as 75% since its discovery in the mid-1980s, principally as a result of over-collection (1).

In recognition of the worrying population decline, the Biznaguita was upgraded to Critically Endangered on the World Conservation Union's (IUCN) 2002 Red List of Threatened Species (1). This cactus is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES) (3), thus restricting trade in wild plants; however, a greater enforcement of these restrictions is required if this attractive cactus is to remain in the wild (1).