Wednesday, July 21, 2010

The weird and parasitic broomrapes

Broomrapes are very strange looking plants. They are not green and do not have leaves. They are parasites and live by taking nutrients from other plants. 

A typical broomrape looks like a brown or yellow fleshy stalk growing out of the soil close to another plant. When fully grown they also have several small unimpressive snapdragon-like flowers growing close to the top of this solitary stalk. 

The plants are seen at the end of winter or during spring. They appear above ground only when it is time to flower. 

During the rest of their lives they live underground closely associated with the roots of a host plan on which they are totally dependent. They have very small seeds that become black with time. The seeds can remain alive in the soil for many years until they are stimulated to germinate by the presence by certain compounds produced by the living roots of a host plant. 

The seedlings put out root-like growth which attaches to the roots of the nearby host. Once attached to a host, the broomrape robs its host of water and nutrient.

There are about 200 species of broomrape of which about 13 are found in the Maltese islands. These include an endemic species and an endemic race. Some species are able to parasite a single plant species. These species are often named after the plant they parasitise. 

One such plant is the endemic Maltese race of the dwarf broomrape. Originally this species parasitised several species of leguminous plant but in Malta it has become a parasite of the Cape sorrel (ħaxixa Ngliża) and in fact in Maltese it known as budebbus ta’ l-Ingliża.

The species shown with today’s article, the common broomrape, is on the other hand a parasite of a large variety of plants of the leguminous and composite families. It can be seen in flower in March and April but is not as common as its name suggests. 

This article appeared in The Times on 10.03.2010

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