Do you know your dragonflies from your damsels - or demoiselles? Photographer Ray Roberts shows us some interesting and beautiful finds down by the river between Liskeard and Callington on his latest nature walk....

I thought another walk down beside the River Lynher was in order so, after parking in the convenient car park at Callington Newbridge I started walking downstream and noticed that some of the riverbank trees had been cut down and left lying beside the path. Why cut down good tall trees and leave them lying I thought?

The first thing I photographed was a damsel fly flitting to and fro across the riverside vegetation and when it pitched, I saw that it was in fact a beautiful demoiselle. This damsel fly prefers fast flowing rivers and has its own territory which it constantly patrols catching small flying insects. It will settle virtually on the same leaf to rest after each circuit and I must have watched this performance for some ten minutes before walking on downstream.

I came to a spot where the river widened and slowed and several pond skaters were skimming to and fro on the surface casting shadows below their bodies and swirls on the water where their feet rest. These long narrow insects have curved beaks with which they attack stranded insects and anything else that floats on the water.

There was a patch of lilac-pink flowered water mint – Mentha aquatica – growing in the damp swampy ground in the riverside woods and it is always a pleasure to run my hand through the leaves to release the most pleasing aroma. There are several kinds of mint, although the plants are really spearmint, that are grown commercially, water mint is wild and it is believed to have been the species that the Romans cultivated some 2,000 years ago. Mint is used in cooking to enhance the flavour of lamb and several other dishes.

I found some more St John’s wort on the edge of the wood, this one was the perforate St John’s-wort – Hypericum perforatum – which has short narrow, leaves with translucent dots on their underside, although a small pocket magnifier would be useful to see them. I photographed the underside of a leaf that was 15mm long and the dots are clearly visible.

During the Crusades, the Knights of St John used this plant to heal the wounds of crusaders, as these dots resembled punctures, which these medieval people saw as wounds. So, if the leaf appeared punctured it was capable of curing wounds, especially those received during a battle.

According to an article on the television news recently, Himalayan balsam – Impatiens glandulifera – is now deemed to be an invasive plant as it spreads itself alongside rivers and streams and inhibiting the grown of our native plants. Mostly having pink/purple flowers but, occasionally some plants have white blooms. These flowers have a unique way of spreading their seeds; when the seed capsules are ripe, they are contained on a catapult that is triggered when touched by bird or animal and the seeds are spread some distance from the plant. The ones I saw beside the river had both white and red flowers and they looked lovely.

There were a few wild angelica plants – Angelica sylvestris – in bloom near the water with their purple flushed stems and white umbels of flowers that are tinged with pink. It is a member of the Umbelliferae or carrot family.