Roy McGhie – Conservation Project Assistant
As my role in the Conservation Department develops I am getting more involved in woodland planting/creation, and woodland habitats. To this end, I recently attended a Field Studies Council weekend course on Identifying Woodland Plants. Over the three days we looked at not only typical woodland wildflowers and trees, but also the bryophytes, ferns and grasses which make up an important part of any woodland ecosystem. Plant identification enables a recognition and understanding of a habitat which then helps inform management.
In the North York Moors we have a lot of ancient semi-natural woodland (ASNW) as well as what is known as plantations on ancient woodland sites (PAWS) where semi natural woodland has been planted up with commercial forestry in the past but where ancient woodland features still persist.
If you walk through a woodland and see combinations of bluebells, daffodils, yellow archangel, celandine, wild garlic you might be forgiven for thinking you are in an ancient woodland because you are looking at typical ancient woodland ground flora. However, all of these species have garden imposters which look similar, and might have been introduced. Yellow archangel (Lamiastrum galeobdolon ssp. montanum) for example, is an ancient woodland indicator species, whilst the garden variety of the plant (Lamiastrum galeobdolon ssp. argentatum) is an invasive plant usually grown as ground cover in gardens. This garden variety of Yellow archangel is classified as a Schedule 9 plant under the Wildlife and Countryside Act 1981 meaning it is an offence to release it into the wild. Quite often the garden imposters are brought into woodlands by people dumping garden waste or tracking seeds in on boots or vehicles. They are therefore usually found on the edges of woodlands at first, but can very quickly colonise inwards.
We spent a large part of the course looking at the species that can be easily confused. These include examples such as Wood speedwell and Germander speedwell, Yellow pimpernel and Creeping-Jenny, Wild strawberry and Barren strawberry as well as trees such as Beech and Hornbeam. When plants are in flower identification can be easy enough but we also focused on vegetative characteristics so as to be able to recognise plants when not in flower. For example, the terminal tooth on Barren strawberry (Potentilla sterilis) leaves is generally shorter than the two surrounding side teeth, whereas on Wild strawberry (Fragaria vesca) the terminal tooth is longer than the side ones. This is an important distinction to make as Barren strawberry can be a good ancient woodland indicator species, whereas Wild strawberry tends to be less so.
Another element of the course was learning to describe why a particular species had been identified as one thing rather than another. It was not enough to point at an English Oak (Quercus robur) and say what it was, we had to explain that it could not be a Sessile Oak (Quercus petraea) because there were intercalary veins (between the apex and the base) on the leaf, leaf auricles strongly present (ear shaped lobes), and a petiole length of approximately 2-5mm (that’s the leaf stalk). Interestingly, we found stellate (star shaped) hairs on the underside of almost all the English Oaks we looked at, suggesting that they were in fact hybrid oaks (Quercus x rosacea), albeit leaning strongly towards English Oak.
Many botanists currently rely upon Clive Stace’s New Flora of the British Isles for their plant ID, and recent taxonomic changes caught out some of the more experienced participants on the course who were more familiar with previous texts. Taxonomy is the hierarchical system used to classify organisms to a species level; it was initially developed during the 18th century and has been adjusted ever since. With the advances in genetic science a number of plants have been reclassified lately according to genetic, rather than morphological, similarity. For example, in the 3rd edition of Stace, Lime trees are now part of the Mallow family (Malvaceae) rather than having their own Tiliaceae family, the Maple family is now Sapindaceae instead of their own Aceraceae family, and Bluebells have changed from Liliaceae (Lilly family) to Asparagaceae (Asparagus family).
Studying bryophytes was a completely new experience for me, and it was fascinating area to investigate. We looked at the main differences between mosses and liverworts, and then broke them down into acrocarpous/polycarpous (depending on location/number of reproductive parts on the plant) and thalloid/leafy groups (depending on plant structure or lack of it). This allowed us to more quickly use a key to then identify what we were looking at. Out of all the ones we identified my favourite was probably Thuidium tamariscinum; it is tripinnate (the layout of the leaflets) and regularly branched giving it a feathery, almost fern-like appearance.
Ferns were also rewarding. We were able to break these down into groups based on how pinnate (compound leaves with leaflets on either side of axis) they were, and how the sori (clusters of sporangia in which the spores form) on the back of the fronds were shaped. For example, the Dryopteridaceae family we looked at were bipinnate and had kidney shaped sori arranged in a row on either side of the mid-rib of the pinnule (division/sub division of a compund leaf). Male-fern (Dryopteris filix-mas) was one such member of this family. It was similar to the scaly male-fern (Dryopteris affinis agg.) but had fewer golden scales, lacked a small dark mark at the rachis (leaf axis) join and the pinnules tended to taper inwards more towards the apex.
Grasses, rushes and sedges can also be ancient woodland indicators. Some of them, such as Pendulous Sedge (Carex pendula) are also common in gardens (and therefore liable to colonise woodlands through being dumped as garden waste), and this served to highlight the importance of always doing a broad survey of any woodland and not assuming it has ancient characteristics based on the presence of only one or two indicator species.
The course finished with a two hour exam in which we had to identify and justify our reasoning for twenty different woody and herbaceous plants. Whilst two hours initially sounded like a lot of time, it meant only five or six minutes per plant, and the time quickly flew by! I actually enjoyed it.
Despite having never previously looked closely at bryophytes or ferns before, let alone encountered terms such as calyx, panicle, auricle and glabrous*, the course had me completely hooked. Some people have dedicated their entire lives to studying single plant families, and new discoveries and species are not infrequent. Now whenever I go into a woodland I’m going to be carrying a hand lens with me – if you do the same you might find that there is a whole world to discover.
*If you want to find out what these words and a host of other botanical terms mean – try here.
Please note that it’s always best to try and identify a plant in the field if possible – take an ID key and a lens out with you. Collecting small amounts of plant material for identification purposes is usually okay, except in the case of protected or (rare) Red List species. But please don’t pick plants if the population at the location is very small and may suffer as a result. If a specimen really is needed for identification, remove the minimum quantity necessary. Please note it is illegal to uproot most wild plants without the express permission of the landowner.