in woodland and protected valleys. In the permanent twilight of woodland white smelly flowers like lily of the valley and woodbine have a distinct advantage with pollinators. Conversely the eddies and coolth of high mountains mean that ‘alpines’ – as they are known to gardeners – are not generally scented. However, in the heather and grasslands of the British Isles other terrifically smelling things abound such as the bog myrtle and the common fragrant orchid.

Undoubtedly white flowers are the most highly scented. The reason that white and light flowers are often highly scented is that they are pollinated by night-flying insects. About 15 per cent of all white-flowered species are scented but only about 9 per cent of red flowers. Red flowers are almost invisible in dim light and tend to close early of an evening. The link between scent and colour in flowers is their function, but it is not all that close. It is accepted that scented flowers, such as night jasmine (Cestrum nocturnum), are often highly inconspicuous, but it is worth remembering that to the small short-sighted insects who pollinate them they are perfectly conspicuous as well as scented.

Smell is the sense for which we struggle to find the right words. We all have difficulty even perceiving the detail in a smell, but the problem is not so much the words; the problem is the fleeting nature of the perception. Perhaps this has led to the side-stepping of the importance of smell: it is so disorderly and, for all its unfathomable complexity, too primitive for words. There are great books on scented planting. Stephen Lacey has published two and my copies are always to hand and well thumbed. There is Roy Genders, a prolific and rather forgotten post-war garden writer whom I often return to, particularly good on scented wild flowers and hedgerow plants, along with long-time hero Richard Mabey. But, good as all these books are, none of them told me how it ‘feels’ to smell Matthiola incana after a shower in April. They don’t attempt, and maybe for good reason, to transduce much beyond ‘sweet’, ‘aromatic’ and ‘spicy’. They don’t leap from the page and exhort one to go out and smell as Thomas Treherne (1636–1674) does, writing on the smell of lilac: ‘It made my heart to leap, almost mad with ecstasy, so strange and wonderful.’ There is something so ardently childlike here, and also in the writings of William Blake, Walt Whitman and Gerard Manley Hopkins and Colette, which encompasses these almost unspeakable emotions.

Latin is a succinct and graphic language, perfect as the universal language of science. I relish the smell words that do get used in botany; they start with the obvious: fragrans, odorata. Sometimes compounded as in odorus mellitus (honey scented) – also melliodorus. Less recognisable are graveolens (strong-smelling) and a favourite of mine, suaveolens (sweet-scented); suavis – sweet; dulcis (sweet also) – as in dulce et decorum est pro patria mori. Thuri is incense – as in thurifer if you were ever a Catholic altar boy; thymi is thyme, and of the teas, but not tea scented. Turpentine or terebinth, coming from the terebinth tree, is terebinthae or, equally, resinae. While velutinus is velvety and fulgens is glittery, fumosus is smokegrey and not smoky-smelling for which there is no word, but formosus means beautiful. Foetidus, foetens and foetulentus all refer to stinkyness; putidus is putrid and stercoreus is smelling of shit. Pungens in Latin means stinging in all senses but became a smell description for botanists. Saccharatus, saccharifera and saccharinus all mean sugary. Nauseosus is a good word. Pudicus means bashful and shrinking and impudicus means shameless and immodest – not ‘stinking’ as I had always assumed, since it is the descriptive part of the name of the common stinkhorn or

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