A short glossary of Latin tree names 

We've compiled a brief glossary of botanical Latin names for the street trees planted in Herne Hill, with their common English equivalents. At Herne Hill Tree Watch we always give the scientific name for a tree after the colloquial name.

Why do we use Latin names for trees?
 

Because colloquial tree names can be very misleading. The hop hornbeam isn’t a true hornbeam, for example, the witch hazel is nothing like a hazel and the false acacia is self-evidently not a genuine acacia.

If you ask Americans to show you a sycamore they’ll point to what we call a plane tree. And if you want to buy a Davidia involucrata, a tree with brilliant white leaf-like bracts, you’ll find nurseries list it as dove tree, handkerchief tree, pocket handkerchief tree or ghost tree.

If you’re serious about trees you’ll soon get to learn the official, scientific botanical name, which is written in a form of Latin known as botanical Latin. It's not really classical Latin at all. It will contain Latinised versions of geographical words or people's names and often bits of Greek. But it will help you navigate tree guides, identify trees on the street or in the wild and get to know their close relatives. And it’s the same name all over the world, which is vital for growers, planters, environmentalists, researchers and commercial operators who all work across international borders.

How does the naming system work?
 

Let's try to explain the naming convention using one of the most spectacular trees in Herne Hill, the Indian bean tree - also known as the Southern Catalpa. Its official name is Catalpa bignonioides (we always write this in italics). The first word of a botanical name - in this case Catalpa - is what's called the genus. In tree books you’ll discover that the genus Catalpa is just one of 79 genera in the wide Bignoniaceae family of related flowering plants.

There are eight recognised catalpa trees in the genus, so bignonioides is what distinguishes this one from the other seven. Together, the two names make up the species. Species names can commemorate an individual, refer to the place where the tree originated or the habitat it grows in, or describe the leaves, flower, colour, shape or fragrance.

Catalpa is a corruption of ‘Catawba’, the name of a Native American tribe in the area of South Carolina where the tree was first identified by the botanist Thomas Walter. The ‘-oides’ bit of bignonioides is a Greek suffix indicating ‘resembling a Bignonia’, a type of flowering plant. Bignoniaceae, then, means a family of Bignonia-like genera.

And what about 'bignon' itself? That comes from Louis XIV's royal librarian, Jean-Paul Bignon, who happened to be the patron of the French botanist and plant collector Joseph Pitton de Tournefort.  Tournefort first named the genus Bignoniaceae in 1694. 

There can also be a third name to describe a cultivated variety of the species, propagated in a garden or nursery. The first letter is capitalised and the word is put in quotes. So if you spot an Indian bean tree with bright yellow-green leaves that will be a Catalpa bignonioides ‘Aurea’. Aurea, meaning golden, is the only part of the name that's genuine Latin.

Alternatively you might see an 'x' in the species name. That denotes a hybrid - a cross between two species. So the London plane is Platanus x hispanica, a hybrid of two different planes. The same goes for the Herne Hill favourite, the  Yoshino cherry, Prunus x yedoensis, a cross between two cherries.

Monsieur Tournefort, who coined the name for the Bignoniaceae, was himself one of the pioneers of botanical classification, or taxonomy, where every plant is grouped into species, genus and family. This system, expanded and refined by the Swedish naturalist Carl Linnaeus in 1735, is precisely the one we still use today. Every single plant fits into it. Among our more common native trees, the English oak species is Quercus robur, within the genus Quercus (the oaks) and the family Fagaceae, which encompasses a thousand species of beeches, oaks and chestnuts. They’re all linked by the nuts that they bear. The 'robur' means strength in Latin, referring to the hard oak timber.

The silver birch is Betula pendula: its genus is Betula (the birches) and its family is known as the Betulaceae. Other members are the alders, the hornbeams and the hazels, and what they have in common is male catkins and female flowers on the same tree. 'Pendula' means hanging in Latin, describing the silver birch branches. 

The Rosaceae family includes the cherries, plums, almonds, apricots and peaches (the genus Prunus), the apples (Malus), the pears (Pyrus), the whitebeams and rowans (Sorbus) and the hawthorns (Crataegus). Roses are part of the same family too, and the feature that connects them all botanically is the structure of the flowers.