The smells related to botany would be almost never-ending if we attempted to include every plant’s smell. Indeed, one plant can emit several smells depending on the stage in its life cycle, and the flower of a plant might smell very different to its leaf, berry, stem, or root (for example, orange fruits smell very different to orange blossom). Herbaria records often include information on a plant’s smell(s), to preserve a written record of scents that are lost in the preservation process. A quick survey of the digitised herbarium records from Kew that are available online through europeana.eu shows hundreds of records that includes reference(s) to smell. For example, a record of ‘Euchaetis longicornis I.Williams’ has a note on its size and dimensions, followed by a note observing that ‘Flowers [are] white and smell of fresh redbait. Leaves smell strongly of Eucalyptus.’ Such information can be vital in correctly identifying plants, and so it is crucial to include a written description where the smell itself cannot be preserved.

As the above example shows, many plants have scents that are uncommon (often even to botanists) and consequently have to be described through similes; for example, with regards to the aforementioned plant, saying that it smells of ‘Euchaetis longicornis’ (i.e. what is actually is) would not help anyone who was not already familiar with the plant, whereas saying it smells like redbait and eucalyptus is more likely to be understood. However, these are several plants that have been used in one way or another for their scent for millennia, and are consequently very familiar: from spices, like cloves and cinnamon, flowers like lavender and rose, or herbs, like rosemary and thyme. The nineteenth-century French perfumer G. W. Septimus Piesse published his work, The Art of Perfumery, in 1857. This seminal compendium of different types of perfume gave an overview of the most popular ingredients to be used in scent, and includes many that would be equally popular today. In the instance of ‘Eau de Cologne’, (the citrusy zesty fragrance which was originally created by the Italian perfumer Giovanni Maria Farina in 1709), Septimus notes that several perfumers have tried (and failed) to replicate it, often by over-complicating it by including ‘all the aromatics of Lindley's Botany’, such as ‘absinthe, hyssop, anise, juniper, marjoram, caraway, fennel, cumin, cardamom, cinnamon, nutmeg, serpolet, angelica, cloves, lavender, camphor, balm, peppermint, galanga, lemon thyme, &c. &c. &c.’ (Piesse: 1857). John Lindley (1799-1865) published several texts on botany and the uses of plants, so it’s unclear which specific text Septimus is referring to (if he is at all), but the point here is that Septimus is satirising the perfumers who over-complicate their formulas by cramming too many botanical items in – less is more, it seems, when it comes to aromatic plants.

While humans regularly derive scents from plants and flowers for their own use in perfumery, the scents emitted from plants are not for our benefit. While many plants emit smells that are intended to attract pollinators and are also pleasant to human noses, some (usually carnivorous plants) emit smells that are intended to attract their prey, and these are usually perceived as unpleasant to human noses. From at least the eighteenth century, scientists began to observe this connection between foul smells and insect attraction, as with the example of the Arum Muscivorum that Linnaeus gives in his Supplementum Plantarum, which Erasmus Darwin describes:

The flower has the smell of carrion; by which the flies are invited to lay their eggs in the chamber of the flower, but in vain endeavour to escape, being prevented by the hairs pointing inwards; and thus perish in the flower, whence its name of fly–eater (Darwin: 1795).

Darwin also reflected on how the ‘odoriferous essential oils of several flowers’ seem to protect them from ‘the depredations of insects’ (Darwin: 1795). While this is true in some instances, it is more often the case that the smell flowers emit is intended to entice insects to them in order to pollinate them.

‘Herbarium’ is also, confusingly, the term given to the storage facilities of herbarium records. For botanists, such places are crucial and perhaps just as informative as studying plants in the wild.

Dr William Milliken, head of Kew’s Tropical America team, describes the herbarium at Kew Gardens as ‘floor-to-ceiling wooden cupboards, boxes and bundles of specimens wrapped in newspaper from the four corners of the globe, and the elusive odour of innumerable exotic dried plants, [which] gives the sensation of walking back in time’ (Milliken: n.d.). Milliken’s comments capture the reality of preserved plants as opposed to their living counterparts – the scent of these plants is elusive and has to be imagined, reminding the recipient that we can no more recuperate the plant’s original smell than we can go back into the past. Similarly, in a blog post for the Royal Botanic Garden of Edinburgh, Alan Elliot commented on ‘the comforting smell of dusty old plant specimens’ to be found upon entering an herbarium (Elliot: 2013), alluding to the smell of the herbarium being not that of plants, but of the materials used to preserve them.

Therefore, the smell of an herbarium is informed by the plants kept in there, but perhaps not in the way we would expect. The odour of the plants themselves is ‘elusive’, and instead we are left with the smell of the mummified ‘dusty’ plants, and the accompanying materials necessary for preserving and storing them – paper and newspaper, wooden cupboards and boxes, ink, glue, and so on.

Aside from herbaria, the other obvious places associated with botany are botanic gardens. Physic gardens have existed for millennia, as a means of studying medicinally important plants. However, over time, the desire to study all plants (not only those with known medicinal properties) slowly developed into the field of botany, and consequently botanic gardens differentiated themselves from physic gardens. Aside from their use to botanists, botanic gardens are usually open to the public. A survey of TripAdvisor reviews for various botanic gardens from around the world shows how often smell factors into the enjoyment of these spaces – the difference being that for the lay visitor, it is the overall scent of the garden that seems to be the most significant factor, as very few reviews pinpoint the scent of particular plants (in the way that a botanist is perhaps more likely to).  Botanic gardens strive to cultivate and curate collections of plants from all over the world in one space – the challenges of creating different climates have largely been mediated through developments in various garden technologies, especially hothouses and conservatories – early examples of which can be seen in this early nineteenth-century depiction of Oxford Botanic Garden (formerly Oxford Physic Garden). Heated buildings to create varying levels of both humidity and warmth further create different smellscapes within the botanic garden – for example, a rainforest house smells very different to an arid house.

On the other hand, when we think of the outdoor places associated with botany, we’re really thinking of any place in the world where plants can grow. There are countless examples of botanists describing the fauna and flora of different parts of the world, but some are perhaps more diverse than others, like South Africa:

The whole country affords a fine field for botany, being enamelled with the greatest number of flowers I ever saw, of exquisite beauty and fragrance (Mason: 1776).

Additionally, many plants can only be truly understood if studied in their natural climate, with the right weather conditions and at the right time. For example, the flowers of Siléne and Cucúbalus are closed all day, but open to give ‘an agreeable odour in the night’ (Darwin: 1795).

Another example is that of the plant that Erasmus Darwin refers to as ‘Nyctanthes, or Arabian Jasmine’, whose flowers give out ‘a most delicate perfume during the night, and not in the day’, but this happens specifically ‘in its native country’. Darwin observes that ‘botanical philosophers have not yet explained this wonderful property’, but perhaps ‘the plant sleeps during the day as some animals do; and its odoriferous glands only emit their fragrance during the expansion of the petals; that is, during its waking hours’ (Darwin: 1795).

Whilst sight has always been essential in identifying plants, vision is sometimes not enough to distinguish between different plants that look similar. Aside from this, knowing what a plant looks like is one thing, but to understand its potential benefits (or dangers), appraisal using the other senses are often also necessary.

For example, the system for cataloguing plants designed by Carl Linnaeus, the ‘father’ of modern botany, entailed eight things that were necessary to include in a plant’s description. Richard Pulteney translated it into English in 1805:

The method pursued in [Linnaeus’ Materia Medica] is as follows, viz.

1. His own specific character of the plant.
2. Bauhin’s synonym; or, if the plant was unknown to that author, the synonym of the first discoverer.
3. The country where the plant is produced. In the same line is expressed, by a single epithet, whether it be a herb, shrub, or tree: whether it be annual, biennial, or perennial: also, whether it be indigenous; or, if not, whether it thrive well by common cultivation in gardens, or require defence from the cold of the winter in Sweden; or whether it will not endure that climate.
4. The Swedish officinal name: what part is in use, or what preparation of it, if any, and the doses of each.
5. The sensible quality of the plant, whether bitter, aromatic, acid, astringent, &c.: whether fragrant, foetid, or inodorous: whether gummy, resinous, or milky. Its reputed quality, whether uncertain, well known, and approved; or whether to be cautiously used. Whether chiefly used in medicine, or for culinary purposes.
6. Its reputed effects on the human body, whether cathartic, emetic, diuretic, &c.
7. The diseases for which it is most frequently prescribed.
8. The compound medicines into which it enters in the Swedish pharmacopoeia. (Pulteney, 1805: 95)

As can be seen, number five moves from the linguistic identification (largely based on visual identification) to the sensory of ‘sensible’ qualities of a plant – namely smell and taste. Knowing this can help in answering numbers six, seven, and eight – i.e., how it effects the body and, by extension, how this might be taken advantage of for medicinal reasons (where possible). This knowledge is consequently inextricable from knowledge of the plants’ uses, benefits, and dangers.

In his translation and collation of Linneaus’ works, Pulteney explained that Linnaeus sought to outline the ‘natural or artificial orders in botany’, and lists some examples of groups of plants which are in ‘agreement in character and qualities’. This includes ‘the stellated class’ which are ‘mostly diuretics’, the ‘asperifoliae’ which are ‘chiefly demulcents’, but also makes a note of the ‘umbelliferous’ plants, which are ‘aromatics’ – particularly their roots and seeds, so long as they are grown in ‘dry places’ (Pulteney, 1805: 361). There is a little bit of horticultural information wrapped up in this – to get the desired aromatic quality from these plants, they must be grown somewhere dry. This also demonstrates that this whole group of plants were primarily valued for their smell.

Aside from using smell to identify a plant whose qualities were already widely known, some were still relatively understudied. For example, Erasmus Darwin refers to the ‘Myria Gale’, denoting that he understands a particular plant to match to this name, but he also notes its ‘agreeable aromatic fragrance’ and wonders if this might make it ‘worth attending to as an article of the Materia Medica’ (Darwin: 1795). Therefore, the smell of a plant could sometimes indicate (rightly or wrongly) that a plant might have a hitherto unrecognised medicinal potential.

Smell could also be employed by botanists as a means of gauging whether something might be safe to eat (although it’s unclear how reliable a system this was!). For example, in 1765 Dr John Hope from the Edinburgh Botanic Garden reported to the Royal Society on some seeds he’d managed to get hold of that were purportedly rhubarb. He was originally somewhat sceptical (as was wise when seeds could easily be adulterated or otherwise unviable). However, he was pleased to report that the plants that grew from them, while not looking like rhubarb that he’d seen before had the ‘smell of the true rhubarb’, which gave him the confidence to taste it; doing so, he initially thought it was ‘soft and mucilaginous’, but ‘soon discovered exactly the taste of the best foreign rhubarb’ (Hope: 1765).

Erasmus Darwin wrote of the ‘dispute’ over whether fungi should be classified as animals or vegetables [i.e. plants]. This confusion stems from the fact that despite appearing to be plants in most senses, they have an ‘animal’ smell and taste when burnt and when they rot (‘insomuch that the Phallus impudicus has gained the name of stink-horn’) (Darwin: 1795). This is an interesting glimpse into how the subjectivity of smell could also lead botanists astray, and how, perhaps, the whole structures of nomenclature in botany are far more fragile than we like to think.

Finally, thinking about exactly how to smell a plant can vary too. Sometimes, for example, the plant’s scent needs to be ‘unlocked’ by rubbing or scratching a leaf. And even then, being able to recall what the scent actually is might, at times, elude even a trained botanist, as in the case of Bradford Torrey in his 1894 account of the flora and fauna to be found in Florida:

‘Here was a pretty shrub. Perhaps I could tell what it was by crushing and smelling a leaf? No; it was something familiar; I sniffed, and looked foolish, and after all he had to tell me its name—camphor.’ (Torrey: 1894).

In an 1862 issue of The Atlantic Monthly, the American botanist Henry David Thoreau recalled his reaction upon first finding a crab-apple specimen; he ‘touched it and smelled it, and secured a lingering corymb of flowers for [his] herbarium’ (Thoreau: 1862).

By ‘secured’ we can assume he means he put the corymb of flowers either in a press or between the pages of a book (which were often used as a makeshift press). This captures the moment of transition between a living specimen and a preserved specimen. The smell present initially will be dissipated as the moisture is pressed out of it, leaving a specimen that will retain little, if any, scent.

Indeed, herbarium samples can appear in stark contrast with their living counterparts, as the scent surrounding them quickly becomes that of the apparatus for preserving and mounting them (paper, ink, glue, wood etc). Looking again to The Atlantic Monthly, this time in 1863, an essay entitled ‘The Utility and Futility of Aphorisms’ written by William Rounseville Alger uses the idea of an herbarium as a simile for writing styles, saying:

To traverse the works of some authors is like going through a carefully arranged herbarium, where every specimen is lifeless, shrivelled, dusty, crumbling to the touch. The writings of genuine men of genius are like a conservatory, where every plant of thought and sentiment, whether indigenous or exotic, is alive, full of bloom and fragrance, the sap at work in its veins. Verbal statements which are petrifactions of wisdom can neither stimulate nor nourish; but verbal statements which are vital concentrations of wisdom do both (Alger: 1863).

The emphasis here (notably from a writer rather than a botanist) is that herbaria contain the ‘petrifications’ of plants rather than the real thing. Consequently, unlike a conservatory full of living plants that are ‘full of bloom and fragrance’, opening an herbarium which has been ‘carefully arranged’ (the implication being that it is captured and curated nature) will only reveal ‘lifeless’ specimens that are ‘shrivelled, dusty and crumbling to the touch.’ Similarly, another article from around a year before in The Continental Monthly described an herbarium as ‘rather faded and seedy’, again emphasising the dusty and somewhat macabre notion that these plants are not truly preserved, and herbaria are only places to keep their corpses (Wolcott: 1862).

In 1748 Dr Laurence Garcin submitted a report to the Royal Society (via Sir Hans Sloane) on the cypress tree, a hitherto little understood and frequently misidentified plant (Garcin: 1748). This report serves as an excellent example of how smell could serve as a useful tool for botanists in identifying plants. Garcin notes that the ancients, like Theophrastus, Dioscorides, and Pliny all wrote with esteem of the ‘Cyprus’ [sic] and noted how highly it was valued, largely for its ‘fine smell, which its flowers sent forth in the countries where they grow naturally, as in Egypt, Syria, Arabia, Persia &c.’ (Garcin: 1748). It has biblical significance, having been mentioned in the Song of Solomon twice, and, Garcin notes, it was used by ‘perfumers in old times’ to make a precious scented oil that was used for various things, but mainly for anointing people to give them ‘a grateful odour’ (Garcin: 1748). Furthermore, he records that Rauwolf observes that people from countries where it grows ‘cultivate this Plant with Care, and even keep it in Pots, on account of the Smell of the Flowers, which somewhat resemble Musk. They keep these Pots in Winter in Chambers or Caves to preserve the Plants from Cold.’ (Garcin: 1748).

The distinctive sweet scent is intrinsically associated with the plant and means that Garcin is able to say that other botanists have gotten it wrong in misattributing the name to plants that do not omit a scent. Indeed, while all cypress plants have this distinctive scent, he adds that those that grow in ‘Malabar’ (an area in southwest India) and other countries where it rains a lot, have an even stronger scent as a result of the rain, as opposed to dryer countries in Persia and Arabia (Garcin: 1748). Garcin relies on the knowledge of indigenous communities, who refer to the plant as ‘henna’; by examining a cypress tree in-situ in Cameroon, he is able to corroborate that henna and cypress are one and the same. It is especially ‘on account of the fine smell of the flowers’ that he is able to confirm that this is in fact a cypress – sight and language alone are not enough (Garcin: 1748).

A similar example comes from the observations of the nineteenth-century Scottish botanist, Isaac Bayley Balfour (1853-1922). In 1874 he accompanied a state-sponsored astronomical expedition to the Mauritian island of Rodrigues and used this as an opportunity to do fieldwork and report on the local flora there. His account was published by the Royal Society in 1879, and gives an insight into how important smell can be in identifying some plants. In the instance of Clerodendrum laciniatum, otherwise known as ‘Bois cabri’ (goat wood), he writes that this small tree is easily recognised by its disagreeable odour, which has occasioned its popular name’ (Balfour: 1879). He notes that the wood is ‘very white and close-grained’ meaning it would be the best wood for carpenters to use, but they instead only use it for burning, due to the stench. Balfour is confident that this is what Leguat refers to when he writes of the ‘nasty tree’ which ‘stinks so, that it makes all the places about “it smell of it, and the smell is very offensive.”’ While some people have thought Leguat is referring to the Bois puant (Foetidia mauritiana, Lam.), the aptly named ‘stinking wood’, Balfour contends that while the odour from that tree is ‘exceedingly objectionable’ it is only apparent when the sun shines upon it, making it ‘evanescent’, unlike the ‘persistent odour’ which the Bois cabri emits (Balfour: 1879). In this instance, Balfour uses his nose to differentiate between two foul-smelling trees that are both endemic to Mauritius by recognising that one permanently smelt, while the other only smelt in the right weather conditions.

The smells to be found from studying plants are manifold, and so too are the feelings that they elicit. Several are greatly enjoyed and appreciated, with distillation and enfleurage being techniques developed as a means of extracting and preserving the scents of flowers, so desirable are they; the perfumer Piesse refers to the ‘exquisite pleasure’ derived from ‘smelling fragrant flowers’, and this is a feeling shared by many (Piesse: 1857).

Sometimes the feeling of pleasure derived from smelling a plant is less about its specific scent, and more due to the indication of its significance in some other sense. For example, when John Hope wrote about trying to successfully grow rhubarb in Edinburgh Botanic Garden, he referred to the ‘taste, smell, colour and purgative qualities’ of the plants that he had grown as being confirmation that he ‘at last possessed […] the true rhubarb’, and his joyful realisation of the significance of this, that he ‘may reasonably entertain the agreeable expectations of its proving a very important acquisition to Britain’ (Hope: 1765). Consequently, the smells related to botany are not only varied but significant in understanding plants and their uses.