Essays on Nature: August 2017

Midsummer can seem a quiet time in the natural world – the riot of spring flowers is over, those chicks that have survived the fledging process have moved on and the birds no longer need to sing to defend their territories or to attract a mate. In the insect world as well, solitary bees have mated and laid eggs for the generation that will emerge next spring, bumblebee colonies have reached their natural end, and summer butterflies are now on the wing. This natural progression through the year, though ultimately driven by the changing day length starts with plants, the base of the food chain. In our lawn/meadow the clovers and vetches that started the floral year, are now dominated by the slower growing and taller plants like ragwort and wild carrot.

Wild Carrot Flower

Wild carrot (Daucus carota carota) is a sub-species with its cultivated sibling, the familiar orange-rooted culinary carrot (Daucus carota sativus). It is an umbellifer, that is, it has a large flat-topped flower head that looks a bit like an umbrella. It is one of the more elegant umbellifers and the buttressed flower heads always make me pause to admire nature’s beauty and complexity. One thing that sets the wild carrot apart from most other umbellifers is that amongst the white florets, right in the middle of the flower head is a dark dot. This dot is actually a couple of florets that are red rather than white. Why should these florets be red? I don’t know, but it is certainly not there so that we can distinguish wild carrot from other species. One likely explanation involves looking at what pollinates the flowers. Bees and bumblebees are rarely seen on wild carrot, they are much more likely to be pollinated by small flies or beetles, like the orange-red soldier beetles that frequently use the flat heads as a mating post. So it may just be possible that evolution has favoured a flower head that contains a dark dot that from a distance looks like an insect already feeding there or perhaps an insect waiting for a mate?

A couple of other wild flowers that are in flower at the moment and can be seen around the village hedgerows are woundwort and black horehound. Both are members of the large mint family, or lamiaceae, which are also known as labiates after their ‘lipped’ flowers. The mint family also contains white dead-nettle that provides such good early forage for our bumblebees. Woundwort has two species – hedge woundwort and marsh woundwort – the names of which clearly indicate where they are likely to be found. Plants with the –wort suffix were used medicinally in the days before large drug companies decided what is good for us, and woundwort was used as its name suggests as a wound dressing. Apparently marsh woundwort was the most effective dressing. Woundwort is very similar to other plants with tall purple flower spikes, and I always check that it is woundwort by tearing off part of a leaf which has a distinctive and unpleasant, slightly antiseptic smell.

Black horehound is another plant with tall purple flower spikes and an unpleasant smell. It has such an unpleasant smell that it has earned the alternative common name of Stinking Roger. It is called black from its dark foliage and to distinguish it from the much rarer white horehound. It is used as a nectar and pollen source for later emerging bumblebees and when we are doing bumblebee surveys, we always check black horehound for the rare ruderal bumblebee, and its rarer cousin the short-haired bumblebee. Plants run a fine line between attracting insects to pollinate their flowers and deterring other insects from eating their leaves which is what the foul smell is all about.