botany — Words of the week

Have you ever noticed a leaf clinging stubbornly to a tree, when all its other leaf friends have long fallen off? There’s a word for that. Marcescence is where something, usually plant matter like leaves or flowers, withers but doesn’t fall off. I can relate.

Oaks and beeches are classic examples of trees with marcescent leaves, which often stay in place for the whole of winter. It’s most common in juvenile plants too. Stroppy teenagers, eh?

Marcescence has its roots (HAHAHAHA) in Latin. Marcēscere means ‘to wither’ or ‘begin to decay’. This comes from marcēre, meaning ‘to be weak or withered’.

Marcescence first made its way into English in the mid-18th century when the study of botany was flourishing (I can’t help myself, sorry), and scientists were coming up with lots of neologisms to describe the natural world. That’s just a fancy way of saying that they were inventing lots of new words.

So how does marcescence happen? Let’s do some science for a sec. In most deciduous trees, a process called ‘abscission’ causes leaves to fall off in autumn. A specialised layer of cells forms at the base of the leaf stem to make this happen. But in marcescent trees, this process doesn’t fully complete, leaving them partially attached. Why? Well, it seems that no one’s entirely sure. There are a few theories though…

It’s for protection: the hanger-on leaves might protect new buds from weather or things trying to eat them. Marcescence is more common in younger trees and on lower branches, which adds credence to this defence theory.
They provide food for the soil: fallen leaves are great for promoting new growth as they rot. The theory here is that by falling off later, marcescent leaves will carry on providing this goodness to their tree long after their pals have gone to the big forest in the sky
To send water to the base of the tree: these leaves could act as a sort of snow fence, slowing down the white stuff and sending moisture to the bottom of the tree where it’s needed most.

There you go. Now you can casually say something like ‘there are so many marcescent leaves around this season’ on your next wintry walk and look well clevs. You’re welcome.

(Oh, and I saw this lovely word in the excellent Tone Knob newsletter, written by my equally excellent ex-colleague Nick Parker. If you’re even a bit interested in writing and tone of voice, it’s well worth signing up. You can do that here.)

If something is filipendulous, it means it’s hanging by a thread or a filament. It’s most often used to describe things that appear suspended by delicate or slender attachments, and look like they could drop at any moment. Like a spider suspended by a single thread. Or my sanity.

Like many of our words (especially the complicated ones), filipendulous comes from Latin. It’s a combination of the Latin word ‘filum’ meaning ‘thread’, and ‘pendere’ which means ‘to hang’.

You’re most likely to come across the word filipendulous in botany, where it’s used to describe plants with structures on fine stalks or threads. There’s actually a genus of plants called Filipendula containing 12 species of perennial herbaceous plants. That includes meadowsweet and dropwort, and the excellently named queen-of-the-forest (Filipendula occidentalis) and queen-of-the-prairie (Filipendula rubra), both of which are native to North America.

Filipendula species are food plants for the larvae of some Lepidoptera (AKA butterflies and moths) species, including the emperor moth, one of the biggest in the world. The largest emperor moth has a wingspan of between 15 and 20cm (6 to 8 inches). Yeesh. (I’ve literally just finished reading ‘The Travelling Bag’ by Susan Hill which makes this fact particularly freaky. If you know, you know.) These moths live in Europe, but haven’t made it across the Channel to us (YET). Having said that, our largest moth is the privet hawk moth, which can get up to a not-too-shabby 12cm (4.7in) wingspan.

You wouldn’t want either of those flapping round your bedroom light, would you?