Nature Notes – The Holly and the Ivy – Mistletoe and Wine
Recent Nature Notes have been bird-orientated. Christmas gives us an opportunity to turn our attention to some plants that feature in Christmas music.
Holly
Holly trees are native to the UK and can grow up to 15 metres high and 300 years old. This is a dioecious plant; it is not self-pollinating. The male and female flowers grow on separate trees and only the female trees produce berries. An unusual feature of holly is its ability to “switch off” traits of its DNA by a epigenetic modification. For example, prickly leaves occur as a defence against browsing animals but in some locations the trees occur with smooth leaves. As noted last month, Mistle Thrushes ‘guard’ fruiting holly trees and drive other birds from the berries.
Ivy
Ivy is a self-supporting, evergreen climber that can grow up to 30 metres tall. Contrary to a common misconception, it does not ‘strangle’ trees when it attaches to them. It is one of the latest plants to come into flower each year. It provides nectar that is especially valuable as a pre-hibernation food source for many insects. The berries that follow are some of the last to ripen; they are hard, and black in colour with a high fat content and are a valuable source of energy to birds such as woodpigeons and thrushes. The Greeks and Romans believed ivy prevented drunkenness and Bacchus, the Roman God of Wine, is usually depicted with an ivy wreath on his head. Historically, ivy was also a symbol of fidelity and a sprig of ivy is often included in modern wedding bouquets.
Mistletoe
The Woodland Trust describe mistletoe as “romantic, parasitic and poisonous”. Balls of mistletoe up to a metre across can be seen high up in deciduous trees, especially in winter when their evergreen foliage is visible amongst otherwise bare branches. Propagation occurs when the white sticky pulp around the seeds attaches a seed to a branch of a potential host tree either having passed through the gut of a feeding bird, or, having been wiped off the beak by a bird, following feeding. The berries that are potentially harmful to humans can be consumed safely by birds.
Wine (Grape Vines)
Wild species of Vitis (grapevine) occur across the Norther Hemisphere. This is another climbing plant that, in its natural state, is dioecious. The Romans introduced wine grape varieties to England and Wales along with knowledge of how to train and prune the vines. Later a range of varieties were brought into the UK by other invaders from Northern Europe. The British climate has not always suitable for production on a commercial scale but in recent years as our summers have warmed, increasing amounts of wine have been produced here. Cultivated varieties are wind-pollinated having been selectively bred to have flowers with both male and female structures.
Cheers!
David Scott
Margaret Budd
