Wellcome Image of the Month: Dandelion

For many, March represents the end of winter and the start of spring, though some controversy still exists over the exact date when the seasons change. In meteorology, spring begins on 1 March, whilst historically it did not begin until the spring equinox on 20 March.

Throughout time flowers have been used in a variety of ways from sources of food or medicine, to national emblems or tokens of affection.

The dandelion (Taraxacum), is considered a weed by some and a versatile, nutritious food source by others. The flower is made up of lots of small florets clustered together into a composite flower head. This month’s image is a transverse section through a dandelion flower bud taken by microscopist Spike Walker. He explained “several florets are visible each consisting of five petals fused into a tube. Inside these are the anthers (pollen boxes) of five stamens (also fused). The anthers are ripe and their walls are splitting to release the pollen. At the centre are the two halves of the stigma (which is forked like a snake’s tongue). The space between the florets is packed with hairs which will eventually form the ‘parachute’ of the dandelion fruit (achene)”. Originally acquired with a light microscope, this image has subsequently undergone solarisation, a technique which alters the tones in the image. In 2010, Spike Walker was awarded the Royal Photographic Society’s Combined Royal Colleges Medal for his ‘outstanding contribution to photography and its application in the service of medicine’. He has also won a total of 24 Wellcome Image Awards to date.

Dandelion flowers mature into a spherical seed head sometimes termed a dandelion ‘clock’. These were used by children to ‘tell the time’ by the number of breaths required to blow away the fruits. This year British summer time begins on 31 March so don’t forget to turn your clocks forward at the end of the month!

Image credit: Spike Walker, Wellcome Images (TS dandelion flower bud, light micrograph)

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