Leaf Shape and Climate

I’ve occasionally peered at a lovely piece of species-rich grassland and wondered a) how all the different species co-exist and b) what benefit the many different leaf shapes convey. Answers on a postcard please. However, I came across some information on one tiny facet of this issue while browsing information about the methods used to infer climatic conditions in the ancient past.

Early in the 20th century two Harvard researchers – Irving W. Bailey and Edmund W. Sinnott  – wanted to establish whether there were patterns in the distribution of leaf shapes across the world’s climatic zones. Through this they hoped to use fossil remains of leaves as a guide to the prevailing climate at the time of their preservation. Their work showed that there is a correlation between cooler climates and toothed leaves in woody dicots. This has now developed into a mature and well-tested method called Leaf Margin Analysis as one of many methods for determining past climatic conditions – which has immense practical relevance in the current climate crisis.

Fuller explanations can be found here and here. These two papers explore some of the reasons for this trend and consider some of the confounding factors. There appears to be a strong link between deciduous trees and toothed margins, perhaps linked to the need to establish photosynthesis in the early spring, but a weaker correlation for other types of plant.

Mendip Hills National Landscape video series

Ecologist, TV presenter, author, and more importantly, SRPG member, Mike Dilger has produced and presented a series of professional videos for the Mendip Hills National Landscape team. This is the new name for the former AONB. These films explain the team’s approach to nature recovery and highlight eight “champion species” around which they will be promoting their broader goal of conserving and improving biodiversity across the area. These include, of course, a short film about the Cheddar Pink, Somerset’s county flower, where Mike is talking to our co-chair Helena Crouch. Quite a few other Mendip plants get some publicity and SRPG gets a few mentions as well.

This year’s meetings programme

This year we have 19 exciting field meetings between April 6th and November 17th. Everyone is welcome but please remember to let the leader that you are coming. Below are some pictures from past meetings.

Read all about it – the 2023 newsletter is here

Now available just over here, our full-colour heavily illustrated record of our doings in 2023. Many thanks are due to all the contributors and especially to Karen Andrews for wrestling the content into this impressive publication. It includes reports on all our indoor and outdoor meetings including our very successful 25th anniversary conference and a number of articles on the following diverse subjects.

Nigel Chaffey provides some in-depth analysis of the form and function of the grass ligule. I always thought it was just nature being kind to botanists, but no, it appears to have two distinct functions! Fred Rumsey has given us a summary of the newly-recognised complications of our smallest flowering plants in the genus Wolffia (Watermeals or Rootless Duckweeds). Ian Salmon has been investigating H.D. Jordan, whose specimens have been added to the Somerset County Herbarium and Helena Crouch reports on a botanical survey of Somerset’s largest island, Steep Holm (largest of two I think but I’m happy to be corrected). As ever there is a summary of interesting plant records for 2023 from Helena and also an update from the dandelion recorders Simon Leach and Jeanne Webb. Happy reading!

Below – a small taster of some of the images in the articles – Henbane on Steep Holm (© Helena Crouch), , a section through the ligule of Millium effusum (© Nigel Chaffey), Taraxacum falcatum (© Simon Leach) and Wolffia columbiana (© Helena Crouch).

Newsletters and botanical history

Some new sections have been added under the Somerset Botany menu. The Newsletters are now there together with an index to all the articles within. There are over 100 articles on a wide range of botanical subjects across the whole county from the Bath area to Exmoor. These include regular updates on interesting plant finds, reports on projects such as the ongoing renovation of the Taunton Herbarium, alien plants and rediscovered natives.

A History section has been added at the bottom of the Somerset Botany menu which currently contains the late Clive Lovatt’s Joy of Botany columns, composed during lockdown, and a presentation by him about George Garlick and Leigh Woods.

A paper in Joy of Botany #5 by Isabella Gifford (SAHNS 1855) includes the following statement on the importance of field botany, a tradition which the Somerset Rare Plants Group is carrying on over 165 years later. Below are some of the botanists mentioned in the history section who worked in Somerset.

The enclosing of commons and waste land, and progress of agricultural improvements generally, must unavoidably destroy the habitats of many rare plants, and in some instances lead to their extinction … . Therefore, it is particularly desirable that a record should be kept of rare indigenous plants. Some few species there are, such as Veronica buxbaumii [now V. persica], which become naturalized in our fields by the agency of the farmer, who scatters the germ unwittingly along with his clover or other seed obtained from the Continent; and though the botanist may not look with an unfriendly eye upon the foreigner, he still feels that it cannot make amends for our native plants …”

Winter meetings programme

We have now completed our season of field meetings and most of the reports are now available. Our winter meeting programme has been sent to members with details of our participation in the BSBI New Year Plant Hunt and our annual members’ meeting at Shapwick Pavilion. This is where we held our Vegetative Plant ID workshop last March. There are some pictures of the venue in the report and below. We will have also have two identification workshops in February and March on winter twigs and conifers, at Carymoor and Fyne Court. SRPG photos © Steve Parker.

Spring Flowers for Autumn

As we approach Autumn here are some reminders of the spring from Simon and Josh, in the form of reports from our visits to Buncombe Wood, Thurlbear Wood, and Barrington Hill. Also recently completed are reports of visits to Otterhead Lakes, which straddles the Devon/Somerset border, and to Weacombe, near West Quantoxhead. Photos © Linda Everton and Simon Leach.

New meeting reports

A number of the meeting reports from this summer are now available. They include the coastal meetings at Berrow Dunes and Sand Bay, an estuarine meeting at Pawlett Hams, and the aquatic plant workshop at Southlake Moor. Berrow Dunes SSSI has long been valued for its rare plants, with 14 Rare Plant Register species being found on this occasion including the spectacular, goat-scented, Lizard Orchid. Sand Bay provided an opportunity to study coastal species at the strand line, on the dunes, and on the saltmarsh. The visit to Pawlett Hams, a large area enclosed by a meander of the Parrett estuary, included freshwater ditches and saltmarsh, with an interesting variety of terrestrial plants along White House Road. The aquatic plants workshop took place at Southlake Moor, beside Barrow Mump, where the ditches are probably some of the most diverse in the county.

Photos below: Knotted Hedge-parsley © Liz Downey, Saltmarsh Rush © Fred Rumsey, Arrowhead © Cath Shellswell

Meeting Reports

If you’d like to hear about some of our outings so far this year, or relive the excitement of the day, you can see them on our Activities > Meetings > Reports page. The reports will appear on the page as they are completed. This year’s programme of meetings is here. Just click on a meeting for further details and contact the organiser to let them know you are coming.