Tuesday, 3 August 2010

High Summer

With the Summer at it's height and the greenery looking at it's best after the recent rain, there are a few plants which seem to dominate the others with their stature. The most impressive of these has to be the Teasel (Dipsacus fullonum). Standing over 7ft tall and covered with formidable spikes, it is impressive indeed.
The name 'Dipsacus', comes from the Latin for thirst (as does the word dipsomaniac!) and refers to the cup-like shape made between the leaves and stems which collect water in little reservoirs. This makes it difficult for sap-sucking insects to climb the stems and may be a form of defence for the plant.
The Flowers of the Teasel are well-known and are held in the familiar, egg-shaped inflorescence. They open at first, in a band across the middle of the flower head and subsequently open in sequence above and below this line reaching the top and bottom of the inflorescence.
The Creeping Thistles of Pewit Carr, have a formidable line of defence too. The prickles are so obviously a part of this defence, but they are of no use when it comes to defending against a small fly, called the Thistle Gall Fly (Urophora cardui). The gall is produced by the thistle plant as a result of the infestation by the grubs of the gall fly which live within. This gall turns from the fleshy green gall seen here, to a hard and woody swelling, so giving more protection to the grubs within.
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