Mammillaria (Mammillaria guelzowiana)

Description

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Mammillaria fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Mammillaria description

Producing the largest and showiest flowers of any Mammillaria species, Mammillaria guelzowiana is a particularly distinctive cactus ⁽³⁾. When in full bloom, the bright, bell-shaped flowers have intense, pink to purplish-red petals with an almost metallic sheen ^{(2) (4) (5)}. The flowers obscure the small, rounded stem, which is depressed at the tip and is covered in spines. The white or tan radial spines are arranged in circles, and are smooth, twisted and hair-like, while the slender, needle-like central spines are reddish-brown to yellow. This species produces rounded, pale, red or yellowish-white fruits ^{(2) (5)}.

The genus Mammillaria is one of the largest of the cactus family, comprising nearly 200 recognised species. The scientific name for the genus is derived from the Latin word ‘mammilla’, meaning ‘nipple’ or ‘teat’, and refers to the protruding tubercles which are characteristic of Mammillaria species ^{(6) (7)}.

Size

Stem height: up to 7 cm ⁽²⁾

Stem diameter: 4 - 10 cm ⁽²⁾

Mammillaria biology

Very little specific information is available on the biology of Mammillaria guelzowiana, except that it flowers in June and July ⁽²⁾.

Mammillaria guelzowiana is a member of the Cactaceae, or cactus family. In general, cacti have evolved to cope with hot or arid environments. The thick, succulent stems have a large volume to store food and water, and are usually covered in a thick, waxy layer which helps to prevent water loss ⁽⁸⁾. The spines present on most cacti are essentially modified leaves, which grow from a unique, specialised structure called an areole. The areole is a sunken cushion of tissue which has two buds (growing points), with spines developing on one, and flowers and fruit on the other ^{(8) (9) (10)}.

The spines of cacti protect the plant from grazing animals, and light-coloured or woolly spines reflect the sunlight, preventing damage from the sun’s radiation. Water also accumulates on the spines of cacti during the night or when it rains, and is then directed down the stem to the roots. The roots of cacti are generally shallow and widespread, allowing them to exploit temporary water sources at the surface. Many species, including Mammillaria guelzowiana, have taproots that go deep into the soil, anchoring the plant and enabling it to obtain additional water and nutrients ⁽⁸⁾.

Mammillaria range

Mammillaria guelzowiana is known only from a small area west of Nazas, in the state of Durango, Mexico ⁽¹⁾.

Mammillaria habitat

Mammillaria guelzowiana occurs on volcanic rocky outcrops on the grassy and semi-desert high plains of Mexico, usually at elevations of around 1,400 metres ^{(1) (2) (5)}.

Mammillaria status

Mammillaria guelzowiana is classified as Critically Endangered (CR) on the IUCN Red List ⁽¹⁾ and is listed on Appendix II of CITES ⁽³⁾.

Mammillaria threats

Mammillaria guelzowiana is threatened primarily by illegal collection of wild specimens, as well as by fluctuating temperature extremes ⁽¹⁾.

The major threats to cacti in general include agricultural development and deforestation, urbanisation, and infrastructure development, such as road building, hydroelectric dam projects and mining. Collection of cacti from the wild for specialist collectors or the horticulture trade also poses a threat to many species ^{(11) (12)}.

A further threat to cacti species, including Mammillaria guelzowiana, is climate change. Climate change may affect species’ physiology, flowering times and interactions with other species, for example with key pollinators ^{(11) (13)}. As a consequence, shifts in geographic distributions may occur. This is of particular concern for species which already have a restricted range, such as Mammillaria guelzowiana ⁽¹⁾.

Mammillaria conservation

Mammillaria guelzowiana is listed on Appendix II of CITES, meaning that international trade in this species should be carefully regulated ^{(1) (2)}. However, enforcement of these laws is lacking in some countries ⁽¹⁾, although Mexico itself has made major progress in succulent plant conservation activities, with existing laws being more effectively imposed ⁽¹²⁾.

Scientists are also actively engaged in research related to cactus conservation. Illegal collecting and the unnecessary destruction of plants have been greatly reduced in recent years, but the decline of many succulent plant populations still continues ⁽¹²⁾. New Mammillaria guelzowiana plants are currently being grown from seed sown in-situ, which should help to counteract the impacts of illegal collections in future ⁽¹⁾.

The IUCN/SSC Cactus and Succulent Plant Specialist Group have recommended that sustained conservation efforts should be coordinated to prevent further extinctions of cactus species. As far as possible, local inhabitants and communities need to be involved in conservation planning to ensure full support for conservation decisions ⁽¹²⁾. Efforts for the conservation of cacti should take into account the effects that climate change may have on the distribution of species, and should be concentrated within the present and future distribution pattern of the species ⁽¹³⁾.

Find out more

Find out more about cactus conservation:

• Oldfield, S. (1997) Cactus and Succulent Plants - Status Survey and Conservation Action Plan. IUCN/SSC Cactus and Succulent Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK. Available at:
  http://data.iucn.org/dbtw-wpd/edocs/1997-041.pdf
• British Cactus and Succulent Society:
  http://www.bcss.org.uk/

Find out more about plant conservation:

• Royal Botanic Gardens, Kew:
  http://www.kew.org

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Glossary

Areole

In cacti, the felted or woolly, cushion-like structures from which spines grow, flowers develop and new stems arise.

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

In-situ

Measures to conserve a species or habitat, that occur inside of the natural range of the species.

Pollinator

An animal that in the act of visiting a plant’s flowers transfers pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.

Tubercle

In cacti, a small wart-like or angular swelling upon the stem.

References

1. IUCN Red List (May, 2011)
   http://www.iucnredlist.org/
2. Cactuspedia - Mammillaria guelzowiana (May, 2011)
   http://www.cactuspedia.info/schede/MAMMILLARIA/Mammillaria_guelzowiana/Mammillaria_guelzowiana/Mammillaria_guelzowiana.htm
3. CITES (May, 2011)
   http://www.cites.org/
4. The Mammillaria Society - Mammillaria guelzowiana (May, 2011)
   http://www.cactus-mall.com/mammsoc/mammofmonth-Jan09.htm
5. Mammillarias.net - Mammillaria guelzowiana (May, 2011)
   http://www.mammillarias.net/gallery/mammillaria_species.php?searchstring=guelzowiana&lg=uk
6. Cactus Guide - Mammillaria (May, 2011)
   http://cactiguide.com/cactus/?genus=Mammillaria
7. San Antonio Cactus and Xerophyte Society - Mammillaria (May, 2011)
   http://sacxs.org/Inside_the_Club/Horticulture/Mammillaria.pdf
8. Dalhousie Collection of Cacti and other Succulents: Biology of Cacti (February, 2011)
   
   http://cactus.biology.dal.ca/biology.html
9. Cactus and Succulent Society of New Zealand (February, 2011)
   
   http://www.cssnz.org/
10. Heywood, V.H. (1978) Flowering Plants of the World. Oxford University Press, Oxford.
11. WWF – Cacti (May, 2011)
    http://wwf.panda.org/what_we_do/endangered_species/cacti/
12. Oldfield, S. (1997) Cactus and Succulent Plants - Status Survey and Conservation Action Plan. IUCN/SSC Cactus and Succulent Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.
13. Téllez-Valdéz, O. and Dávila-Aranda, P. (2003) Protected Areas and climate change: A case study of the cacti in the Tehuacán-Cuicatlán Biosphere Reserve, México. Conservation Biology, 17(3): 846–853.