Euphorbia (Euphorbia bongolavensis)

Euphorbia fact file

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

Euphorbia description

Euphorbia bongolavensis is a member of one of the largest and most diverse flowering plant families in the world, the Euphorbiaceae ^{(5) (6) (7)}, which contains around 7,500 species ⁽⁶⁾. The shape and size of the leaves of Euphorbiaceae species are highly variable, although they are usually deciduous and the leaf stalks are often reduced to thorns ^{(6) (7)}. The succulent Euphorbia species found in Africa and Madagascar are similar in appearance to the cacti of North and South America ⁽⁷⁾.

The peeling bark on the stalk of Euphorbia bongolavensis is arranged into thin rings. There is a rosette of egg-shaped leaves at the tip of the stalk, which are bright red at the base ^{(2) (3)}.

This species in included in the genus Euphorbia, characterised by their extremely simple flowers ⁽⁸⁾. Species within this genus have a miniature inflorescence called the ‘cyathium’, which has a single female flower in the centre surrounded by several male flowers. All of the flowers are enclosed in the ‘involucre’, a series of bracts arrange in a cup shape ^{(5) (6) (7) (8)}. Nectar-producing glands can usually be found between the bracts ⁽⁶⁾. This unique feature is not seen in any other genera of the plant kingdom, although some Euphorbia species do not possess this feature ^{(5) (6) (7)}.

The fruit of Euphorbia species is an explosive capsule which bursts open when it is ripe, shooting out three or more seeds with a huge force ^{(5) (6) (7)}. The shape and size of these capsules is highly variable ⁽⁵⁾. 

Size

Height: up to 100 cm ^{(2) (3)}

Euphorbia biology

Very little is known about the biology of Euphorbia bongolavensis, although it is known to be a dioecious species, with the male and female flowers on different plants ⁽²⁾.

The primary pollinators of most Euphorbia are flies from the order Diptera, which are attracted to the brightly coloured bracts and the nectar-producing glands on the cyathium ⁽⁵⁾.

Many species of Euphorbia are known to exude a milky, toxic latex when the stems, roots or leaves are damaged ^{(5) (6) (7)}. The latex is usually poisonous and may have developed as a defence mechanism against herbivores ⁽⁵⁾. 

Euphorbia range

Euphorbia bongolavensis is endemic to north-western Madagascar, where is is only known from one location, in the Bongolava Mountains ^{(1) (2)}.

Euphorbia habitat

Euphorbia bongolavensis is found in dry montane forest ^{(1) (3)}.

Euphorbia status

Euphorbia bongolavensis is classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾ and is listed on Appendix II of CITES ⁽⁴⁾.

Euphorbia threats

The greatest threats to Euphorbia bongolavensis are the increasing agricultural industry and burning for the charcoal industry, which are reducing the size of its habitat ^{(1) (9)}. This species is also collected for horticulture ^{(1) (5)}.

Euphorbia conservation

Euphorbia bongolavensis is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning international trade in this threatened plant should be carefully controlled ⁽⁴⁾. No other specific conservation measures are currently in place for this poorly known species. 

Find out more

Find out more about Euphorbia species:

• International Euphorbia Society:
  http://www.euphorbia-international.org/
• Euphorbia Planetary Biodiversity Inventory project:
  http://www.euphorbiaceae.org/index.html

Find out more about African Euphorbia species:

• PlantZAfrica - Euphorbia:
  http://www.plantzafrica.com/plantefg/euphorbia.htm
 

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Glossary

Bract

Modified leaf at the base of a flower.

Deciduous

A plant that sheds its leaves at the end of the growing season.

Dioecious

Male and female flowers are borne on separate plants.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

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.

Gland

An organ that makes and secretes substances used by the body.

Herbivore

An animal that consumes only vegetable matter.

Inflorescence

The reproductive shoot of a plant, which bears a group or cluster of flowers.

Montane

Of mountains, or growing in mountains.

Pollinators

Animals that in the act of visiting a plant’s flowers transfer 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.

Succulent

In plants, species with thick, fleshy, water-storing stems and leaves.

References

1. IUCN Red List (July, 2012)
   http://www.iucnredlist.org/
2. Bonn University (July, 2012)
   http://www.uni-bonn.de/~ulp50021/euphorbiabongolavensis.html
3. Eggli, U. (2004) Illustrated Handbook of Succulent Plants:Dicotyledons. Springer-Verlag, Berlin.
4. CITES (July, 2012)
   http://www.cites.org/
5. Euphorbia Planetary Biodiversity Inventory project (July, 2012)
   http://www.euphorbiaceae.org/pages/about_euphorbia.html
6. International Euphorbia Society (July, 2012) 
   http://www.euphorbia-international.org/
7. PlantZAfrica (July, 2012) 
   http://www.plantzafrica.com/plantefg/euphorbia.htm
8. Heywood, V.H. (1978) Flowering Plants of the World. Oxford University Press, Oxford.
9. 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