Friday, March 8, 2013

The Maltese spruge

Maltese spurge - Tengħud tax-xagħri (Euphorbia melitensis)
As its name suggests, the Maltese spurge is a plant endemic to our islands and belongs to the spurge family. It grows as a dense shrub usually about half a metre high, although in some places it can grow up to two metres.

The Maltese spurge, known as tengħud tax-xagħri, grows in garigue. At particular times of the year, it can be mistaken for a thyme bush from a distance. This is a result of convergent evolution – when two species have the same characteristics even though they are unrelated.
In this case these unrelated species share many features as a response to the difficult conditions in which they live. A dense, bushy shape and small waxy leaves help to reduce water loss.

Spurges also have a mechanism to defend themselves from herbivores such as wild rabbits and domesticated animals, such as goats and sheep. They produce a poisonous white liquid which can be seen when a part of the plant is damaged and that makes them inedible.
However, this liquid does not protect them from the caterpillar of spurge hawk moths which feed on its leaves and accumulate the poison in their body to protect themselves from predators.
The spurge hawk moth is another endemic species and is known as the Maltese spurge hawk moth.

The liquid is also ineffective against dodder, a parasitic plant known in Maltese as pitma, that obtains its nutrients from its host plant.

The Maltese spurge was first described in 1869 by Filippo Parlatore, an Italian botanist from Palermo. Parlatore was a medical doctor who gave up his profession to be able to devote all his time to botany. He published works on the flora of Sicily and as at that time many naturalists considered Malta to be part of Sicily, he included information about Maltese flora in his studies.

This article was published in The Times on 27 February 2013

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