The time has come the walrus said ...

Many trees are planted for their spring blossom, providing a splash of colour in an otherwise still rather drab post-winter landscape. All trees have flowers, either insect or wind-pollinated, but insect-pollinated flowers are larger and more showy: if the flowers appear plain white, they are usually richly patterned in the ultra-violet wavelengths visible to insects. It is not always visually clear whether a flower is insect-pollinated or not, but the presence of often strong-smelling nectar provides confirmation. Below are images of ten such insect-pollinated trees. Wild Cherry ( Prunus avium ) When one thinks of trees and flowers, the blossom of Japanese cherries immediately springs to mind. Japanese cherries are carefully bred and selected cultivars, nearly always grown by grafting onto a rootstock of Wild Cherry. In the British countryside Wild Cherry is the only large-flowered large woodland tree. Common Hawthorn ( Crataegus monogyna ) In May, after the Myrobalan Plum and th...

It is a truth universally acknowledged ... that when you have a group of people living in some place A, some of them will wish to be in place B, and vice versa, hence travel. But how has travel changed over the last 2000 years? Let's have a look at the case where place A is Cambridge and place B is London... Precisely 2000 years ago in AD20 there may not have been much travel between the two, as London didn't really exist and Cambridge was in a different tribal region. However Claudius launched the Roman conquest of Britain in AD43, and by AD47 the whole south-east had been subjugated. Roman Cambridge, named Duroliponte, was founded around AD70, initially as a miltary camp on the site of an Iron Age fort. London, founded soon after the Roman invasion, was burnt down by Boudicca in AD61, but soon bounced back. Before long the Romans had constructed an extensive road network. London was connected to Cambridge by Ermine Street, which ran from Bishopsgate in London along the rout...

Wind pollination is an inefficient option for a tree, as there is a very low probability of a pollen grain landing by chance on the stigma of suitable recipient flower. But, on the other hand, suitable insect pollinators don't thrive in the British climate, particularly in the cooler countryside. Hence a high percentage of native or naturalised British tree species are wind-pollinated. Their flowers are not so flashy as those of insect-pollinated species, but at close range they reveal an intricate beauty. Below are nine such wind-pollinated species. Goat Willow ( Salix caprea ), one of the so-called 'pussy willows' has one of the most striking wind-pollinated flowers. The female flower before opening is soft enough to stroke (in the first picture the styles have extended and the yellow stigmas pushed through the grey hairs). The male flower is equally striking with long yellow-anthered stamens. White Willow ( Salix alba ) has longer catkins closer to the common percept...

The rich variety of leaf shapes on deciduous trees make their identification relatively easy in the summer months. Some tree guides offer silhouettes of the denuded trees as an aid to their winter identification. In practice this is difficult, as not only are the differences often quite subtle, but you need a free-standing tree, both for it to adopt its textbook shape, and to be able to see it clearly. Bark can be a helpful identification aid, but only for a limited range of trees including birches, cherries and poplars. I have found it much easier to identify trees in winter (at least to the genus level) by means of their buds, and have found the rich variety of buds a source of endless fascination in itself. Below I offer pictures of the buds of ten common deciduous trees to give some indication of the range of bud types that may be found. Of course, even before looking at the bud itself, the arrangement of buds helps distinguish opposite-leaved and alternate-leaved trees. Most twi...

Is it possible to define a globally applicable, height and prominence-free definition of a significant hill? As a child I could reel off the highest points in each continent and in numerous countries around the world. Soon after we were married, my wife and I made a point of climbing the highest summits at least in England, Wales and Scotland, although tentative plans to work through the Munros ground to a halt after three Cairngorm summits plus Schiehallion. All hills are worth climbing of course, because they're there, but are some hills more worth climbing than others? There are many lists of hills out there, of which the Munros are by far the most famous. But, stuck in East Anglia, with even the Peak District barely in range, and certainly nothing approaching 3000 feet, does that mean one should give up? Well, even in the South-East there are Marilyns. The definitions of a [significant] hill seem so arbitrary though, 3000 feet for Munros, 2500 feet for Corbetts, 150m promine...