Woodland Flowers

‘The wandering botanist is naturally mistaken for a tramp off the beaten track, or for an officious inspector of something or other’, wrote Arthur Church in 1922. This quotation does rather sum up my career: from scruffy student researcher, through besuited civil servant, back to the grey-haired wanderer in the woods. More serious tramps and inspectors, the professional and enthusiastic botanists (such as Church himself) recording plants over the last 600 years, have generated the knowledge on which this book is based; and people still go out to survey woods for plants to help with their conservation or just for fun.

We don’t know when our ancestors first started looking at plants as more than just something to eat or to avoid, but it may have been before we were even Homo sapiens. From early times there must have been an appreciation of which trees made the best firewood, which greens could be eaten, which might heal the sick and which might kill. The remains of flowers have been found in prehistoric graves and ritual deposits. A considerable a mount of what we would now consider basic natural history was understood in the ancient world, although this might run alongside discredited ideas such as the ‘doctrine of signatures’. This last suggested that similarities between the appearance of plants and disease symptoms meant that the plant could be used to cure that disease.

The Ancient Greek Tyrtamus (usually known as Theophrastus, born c.370 BC) wrote about the herbal properties of many plants, but also other aspects of their growth. For example, he reported that both male and female plants contributed to the production of seed, at least for some plants – an early appreciation of the role of pollination. Moving plants from one place to another was known to sometimes increase yields but also to cause greater vulnerability to frost – an issue for us, if we wish to translocate species in response to climate change. Stirring up soil led to new vegetation growth, from, as we now know, buried seed (Hort 1916). He referred to the problem of naming plants precisely because misidentification could have serious consequences: Theophrastus was concerned that the three plants referred to as ‘strykhnos’ had distinct properties: one was edible and like a cultivated plant, having a berry-like fruit; one was said to induce sleep; the third (Thorn Apple Datura stramonium) to cause madness or death. Even today, many of the specimens in botanical collections around the world are not correctly named. There is also a link to my doctoral research in that Theophrastus recognised the great variety of brambles and that they might spread by stems growing down and rooting at their tips, something I studied at Wytham.

Much of the classical world’s knowledge of plants may have been lost or corrupted in early modern Europe, but some was passed down through Arab and then medieval scholars (Pavord 2005). Those who lived and worked in the countryside might have known many locally-growing species, if they had cause to collect them for culinary or medicinal purposes, while those whose business was with other matters might know only one or two species. We see the same thing today when the first-year undergraduate students in biology come on a field trip; there are some who are already good botanists, but others struggle over anything less obvious than a Bluebell.

Gradually, herbalists such as William Turner of Morpeth (c.1508–1568) started to record what our plants really looked like, what they did, and to give them distinct names. Turner’s writings include at least 250 species. The invention of printing made it possible to spread this information widely. A near contemporary, John Gerard, published his ‘Herbal’ (a book describing plants and their uses) in 1597. This had many errors, but after his death an ‘enlarged and amended version’ by Thomas Johnson was published in 1632. Thomas Johnson also produced the first plant list for England and Wales (1634, 1641), Mercurius Botanicus (Pearman 2018). Out of about 270 woodland plants in Great Britain for which there is a date for a first record in print, 200 were published before 1700. Our flora was becoming well-documented, although the distinctive elements of the Scottish Highland flora would not be described for another century.

Gradually, systematic lists were produced of locations where plants occurred. John Ray (1627–1705), an early modern botanist, compiled the first regional catalogue, of the plants around Cambridge, in 1660, which was based on direct observations and collecting (Preston & Oswald 2012). Over 600 species were named, with habitat details for three-quarters of them. Crested Cow-wheat Melampyrum cristatum, for example, was described as growing plentifully in almost all woods; now it is a rare species that is carefully nurtured along the margins of Monks Wood National Nature Reserve. Others of Ray’s notes are more practical – ‘the young stems of Burdock can be eaten in salads, raw or cooked’.

The consistent naming of plants remained a problem, as it had been for Theophrastus (Pavord 2005). Ray proposed some principles for classifying plants that were simple but efficient: names should be changed as little as possible to avoid confusion; related plants should be grouped together; the characteristics of a species should be clearly defined; the minimum number of characteristics possible should be used; the characteristics should be obvious and easy to grasp (this one has been challenged by modern classification, which uses DNA analysis!). Even so, species were still usually named according to a, sometimes cumbersome, description of their characteristics. This was simplified through the development and promotion by the Swedish botanist Linnaeus (1707–1778) of the system of two-word scientific names used today.

One specimen of a plant was chosen as the ‘type’ specimen; its description then became the reference with which any future collections are compared. Linnaeus’s collection of botanical specimens came to Great Britain after his death and is still held by the Linnaean Society in London. It includes his ‘type’ specimen of the Twinflower, which was apparently his favourite plant. Twinflower was given the scientific name Linnaea borealis by another botanist, because it is not done to name a species after yourself!

The Apothecaries’ Act of 1815 brought in compulsory apprenticeship and formal qualifications for what would now be termed medical general practitioners. They were expected to be familiar with a variety of plants used in healing, and this stimulated botanical teaching at universities. Later in the Victorian era and the early 20th century there was a more general upsurge of interest in natural history. Drawing and collecting plants became common pastimes as illustrated by Elizabeth Holden’s nature notes of 1906, which became a best-seller after they were rediscovered and published in 1977 as The Country Diary of an Edwardian Lady.

Plant records were brought together in books that listed for each county the species found, with notes on their distribution, commonly called ‘county floras’. Such collations for Northamptonshire, Oxfordshire, Berkshire and Buckinghamshire were all written by one man, George Claridge Druce (1850–1932), who was also very involved with the Botanical Society and Exchange Club of the British Isles, a forerunner of what is now the Botanical Society of Britain and Ireland (Allen 1986). Druce had trained as a pharmacist and later owned a chemist’s shop in Oxford. His early interest in the plants and animals around his childhood home in Northamptonshire matured into a collection of over 200,000 specimens. Other individuals and institutions built up herbaria, even if not on the scale or of the quality that Druce achieved. Many were no doubt what May Coley (1932) in her guide to botanical etiquette would call ‘mournful collections’, with poorly presented or incomplete specimens. The better collections are now, however, being used to explore the past distribution of species; as sources of DNA to look at the evolution of species; and also to see how flowering times have changed (chapter 16).

A low, insignificant plant?

The Twinflower Linnaea borealis is a common plant in the northern Scandinavian forests that Linnaeus encountered on a trip he made through Lapland in 1732. Later he described it as ‘low, insignificant, forgotten, flowering for a short time; it is named after Linnaeus, who resembles it’. He may have been suffering from depression when he wrote the above comment, or was it just false modesty, since he was quite a self-publicist? The association with Linnaeus led to this being one of the most common plants in the world’s herbaria, with tens of thousands of specimens collected from across its range (Stephen Harris, personal communication).

For today’s botanists in Britain, Twinflower is not so insignificant, because it is one of the group of species that are largely confined to the pinewoods of Scotland, making their flora different to woods elsewhere in the country. Twinflower is found in both native and planted pinewoods, and occasionally turns up in birch–oak woods usually in light to moderate shade. Its low stature means that complete removal of grazing from sites is undesirable because the increased vigour of plants such as Bilberry may over-top it. Flowering shoots bear the eponymous two flowers, which are pollinated by solitary bees and hoverflies.

Twinflower disappeared from many sites prior to the 1930s because of woodland clearance, and it is still declining in Great Britain, both in terms of losing patches and reduction and fragmentation of individual patches. It is potentially at risk from climate change because its northern distribution suggests that it may grow less well as conditions get warmer. The main spread within a site is from shoots creeping through the moss carpet. The shoot connections eventually break down, and many apparently separate patches may be the same clone (Eriksson 1992, Wiberg et al. 2016). Self-fertilisation is rarely successful, so poor seed production reduces the chances that the plant can colonise new sites (Wilcock 2002, Scobie & Wilcock 2009).

To try to overcome this problem, plants from different sites which are likely to be genetically different have been planted around an existing Twinflower patch as part of conservation projects in the Cairngorm National Park. This should increase the chances of cross-fertilisation and seed set. Plants of 11 separate clones are being grown on, and four new mixed populations have been planted out at one site, with each population having a minimum of five clones to improve the chances that flowers will be cross-fertilised. The plans are to repeat this at other sites (Diana Gilbert, personal communication).

Twinflower has been recorded from time to time in northern England, but, like some other pinewood specialists, these records are usually treated as introductions, possibly associated with tree-planting. The same may be the case for some of the records from the lowlands of northeast Scotland (Welch 2003).

Twinflower growing in a Scottish pinewood.

Collecting could be overdone. Arthur Church (1922) complained that people would ‘devastate hedges and woodland, grabbing all available specimens of rarer flowers of aesthetic value for alleged decorative purposes’. He accused collectors of showing no compunction about taking rare plants for their herbaria or to exchange with other botanists. Giving the locality for a rare or interesting plant might be to sign its death warrant, although this was not a new concern. John Ray in 1660 noted that some species he listed might have been completely eradicated and carried off by root-collectors. Even today, botanists may be reluctant to publish precise coordinates for rare species, and the public records are fuzzied-up on maps.

Excessive collecting might have other consequences. May Coley wrote that ‘Too much cannot be said against greedy and destructive gathering, so largely responsible for the closing of many secluded woods that might otherwise be open to the public’ (Coley 1 932). Certainly, in the late 19th and early 20th century the opportunities for casual botanising were starting to diminish. Common rights were being abolished, or simply not exercised, as the number of people living and working in the countryside declined. Privately-owned land became more private, particularly if game birds were involved. In the uplands the public were discouraged, even banned, from moors keepered for grouse and deer, while in the lowlands Arthur Church noted that woods were ‘becoming more and more closed against the public and the favourite collecting grounds of an older generation of botanists are destroyed or are no longer available’.

By the beginning of the 20th century the British flora was pretty well-defined, with fewer and fewer new species being added to the list, except amongst introductions and difficult groups such as brambles, Hawkweed Hieracium spp. and Dandelion Taraxacum spp. Identification guides allowed people to name plants through the use of keys based on descriptions, and sometimes drawings, of the species. The seventh edition of Bentham and Hooker’s British Flora for example was my sixth-form biology introduction to the intricacies of the parts of a flower, the petals and sepals, stigmas and stamens, inferior and superior ovaries (Bentham et al. 1930).

Bentham et al.’s books were overtaken by Clapham, Tutin and Warburg’s Flora of the British Isles, affectionately known amongst botanists as CTW (Clapham et al. 1962). This was for many people the standard work through to the 1980s. Other publication landmarks were the Reverend Keble-Martin’s illustrations, Roger Phillips’s series of photographic guides and Francis Rose’s The Wild Flower Key (Keble-Martin 1965, Phillips 1977, Rose 1981, Rose & O’Reilly 2006). In recent years there has been the replacement of CTW by Stace’s New Flora of the British Isles (Stace 2 010). Plant identification often focuses on the flowers, but in woodland the heavy shade may prevent plants from producing any. Fortunately, one of the more recent guides is to plants in their vegetative state (Poland et al. 2009).

A different sort of landmark publication was the first Atlas of the British Flora produced by the Botanical Society of the British Isles (BSBI) in 1962 (2nd edition, Perring & Walters 1976), which showed the distribution of species by 10km squares (chapter 4). As with Geoffrey Grigson’s study of plant names and uses, the timing proved to be critical: many of the records for where plants grew predated the effects of the post-war intensification in farming and forestry and the spread of urban development. The atlas thus acted as a baseline against which to show subsequent trends (mainly losses, but some gains) for different groups of species. A second atlas was produced for the millennium (Preston et al. 2002).

When the two atlases are compared, common species tend to have maintained their distribution and abundance; species that are tolerant of fertile conditions are more likely to have increased since 1962 than those found on infertile soils. Plants of shady conditions have generally done better than those of open conditions. Species associated with broadleaved woodland, for example, showed little change compared to the sharp declines for the weeds of arable fields. A third atlas project is currently under way.

My age and upbringing mean that I still mainly use books for identifying plants, but students on our first-year field course use their iPhones to pull up pictures of plants they are unfamiliar with. Photographs can be identified using apps such as iSpot, and the tedious business of plotting records by hand to produce a distribution map has been automated through use of spreadsheets, Geographic Information Systems (GIS) and Geographic Positioning Systems (GPS). Web technology has made it possible for people to access past records through the National Biodiversity Network, a partnership of organisations committed to sharing biodiversity information. It already holds more than 200 million records. However, whether you record using pen and clipboard, or hand-held data logger, identify plants from a book or the internet, you still have to go into the woods to find them.

The atlases produced by the BSBI map plant species by 10km squares and these can be used to give a national picture of species-distribution changes, but that does not tell us what has been happening to the plants in any individual wood. More detailed records are needed for that, and the simplest way of making a list is just to go on a ‘walkabout’ (Kirby & Hall 2019). Plot a route through the wood that aims to see as much of the ground as possible, picking up any obvious variations such as streams and glades, woodland edges, or variations up and down the slope. You can get an overview of what a wood of 20–30ha is like in a day by this method, with typically between 50 and 120 woodland species likely to be found.

Species can be allocated to abundance categories such as Dominant, Abundant, Frequent, Occasional, Rare (the DAFOR scale). Most will fall into the Occasional/Rare categories, with just a few Frequent or Abundant. This system is useful, but rough and ready. It does not allow for precise statements to be made about the composition at specific points in the wood; comparisons over time between two walkabout surveys are difficult because what I call Abundant, you might call Frequent. Small, ‘difficult-looking’ plants may be ignored, in the hope that either they are something already recorded, or that a better specimen will be encountered later on in the walk.

Other botanists look in detail at a series of points using (usually square) plots or ‘quadrats’. A fixed area of ground is defined, for example with a tape measure, and this is then systematically searched for plants. This forces you to look at the difficult areas (dense thickets) as well as easy ones, and all plants within the quadrat, even the awkward little ones, have to be considered. This standardised approach allows for quantitative comparisons to be made between quadrats placed in different parts of a wood, and between woods. In grassland, quadrats tend to be quite small, 1 × 1m or 2 × 2m, because species in grassland are usually tightly packed. This is nicely illustrated by Albrecht Dürer’s famous painting Der Grosse Rasenstück (The Great Piece of Turf), which shows a range of grasses and herbs. In woods there are often swathes of just one species (Bracken, Bluebell, Ivy, Bilberry) or large patches of bare soil or litter in between clumps of plants. Small quadrats are not so useful, because they might contain only one or two species which would not make as exciting a painting!

Because of this, woodland surveyors tend to work with large quadrats, varying from about 4 × 4m as the smallest size in common use, to 14.1 × 14.1m or 30 × 30m. The larger the quadrat, the more species are likely to be found in it, but it takes more time to survey each one and there is a greater chance that species will be missed. Fewer quadrats can be recorded in a day. As a convenient compromise I usually use either 5 × 5m or 10 × 10m plots. The number of species found may not be much more than is found in the smaller areas sampled for grassland surveys, with generally fewer than 20 vascular plants in a 10 × 10m plot under shade and, occasionally, none at all.

The surveyor may deliberately place the quadrats to aid the description of a typical patch of woodland vegetation or a particularly unusual area. Alternatively, the quadrats may be distributed at random or as a systematic grid through the wood, so that statistically-valid analyses can be performed on the data. Other measurements such as the size and cover of the tree layer or the soil characteristics may be made at the same time as recording the ground flora. The variations in the distribution of plants can then be related to these other factors, such as the degree of shade, soil acidity, recent management, or evidence of browsing.

Quadrat recording involves more systematic and thorough recording than just listing plants seen on a walk, but a much smaller area of woodland is actually seen. Many species may not be picked up, because they happen not to be present at the spots where the quadrats have been placed. Six of us spent a good part of one spring and summer looking at how many species were found according to the number of quadrats recorded or the time spent on a walkabout through the same bit of woodland (Kirby et al. 1986). In Wytham we could easily pick up 80 species in the course of a three-hour walk; but to get that number of species recording quadrats through the same area took about twice as long. There was a similar result from the woods surveyed in Wales and Scotland. So, it depends on the objectives of your survey, as to which method is most appropriate, and if there is time, a combination of the two gives the best of both worlds.

If the quadrat positions are recorded precisely enough, then it is possible to return to the same spot some years later and see exactly how things have changed. I inherited from my supervisor the results from two such sets of permanent quadrats, established in the 1970s. One is at Wytham Woods, the other at the Warburg Reserve in Bix Bottom in south Oxfordshire. The first recordings were in 1973 and there have been several re-recordings since. Two overriding lessons emerge from these efforts. The first is how difficult it can be to re-find quadrats in woodland, even if you know that the quadrat is close by and that there are buried metal markers at its corners; the second is that the woodland flora can be much more variable over time than might at first be expected (Kirby & Thomas 2000).

Common plants can become rare, while rare plants may go locally extinct, and new plants may colonise a wood and start to spread. In Wytham Woods, between 1974 and 1991, Bramble went from being the dominant plant over large areas, to making an almost insignificant contribution to the structure of the ground flora. By 2018 it had recovered enough to become a trip hazard again. The grass False Brome Brachypodium sylvaticum was scarce in these woods in the 1970s but is now locally dominant.

The Wytham work is only one of many local and national surveys of woodland vegetation organised during the last half of the 20th century (Peterken 1993, Kirby et al. 2005). In the late 1970s and 1980s I spent a lot of time travelling round the country looking at woods with clipboard in hand and quadrat poles on my back. Many others were similarly engaged, as conservation organisations took advantage of funding available under the then Government’s job creation programmes.

The results fed into the refinement of the woodland species list and into maps of the national distribution of species. Another major project set about looking at which species regularly grew together and how such groupings, sometimes called assemblages or communities, relate to soil conditions (chapter 5), climate differences across the country, or the effects of past management. These assemblages form what is now called the National Vegetation Classification (Rodwell 1991), described in chapters 6 and 7. However, one significant finding from the 1970s, arising from woodland surveys, was that old maps could be a useful way of identifying where rare and unusual woodland plants might be found, as discussed in the next chapter.