Sorting Centaurea in the British and Irish Herbarium Collection | Identification Trainers for the Future

Curation is a key part of the Identification Trainers for the Future programme and over the past 2 months the trainees have been on placement in the Museum collections learning how best to preserve the historical and ecological information held within them. Following on from Anthony’s review of his time with the Odonata collections, Sally Hyslop brings us up to speed with her own project:

My curation placement is in the British and Irish Herbarium, working alongside Mark Spencer, the senior curator of this impressive catalogue of pressed plant specimens.

Photo of a desk with two plant presses and a selection of herbarium sheets in between
Working with plant presses for the British and Irish Herbarium

Each specimen in the herbarium holds information – whether it be from the DNA stored within the plants themselves waiting to be extracted and studied, or the historical annotations which depict the collection event itself. All specimens in the collection have a label describing the all-important who, what, where and when.

The date, location, name of the collector and the collector’s original identification is essential information which can further our scientific understanding.

Recorded dates and locations can be used to map the distributions of species, whereas flowering times can be used to better understand how species respond to climate change. Combined, the thousands of specimens build up a detailed picture of UK biodiversity. They provide insights into the past and may help inform predictions for the future.

Photo of a herbarium sheet showing specimen and labels
Labelling of specimens provides the all important what, who, where and when of collection

My first task on my placement has been to help re-curate specimens recently donated to the Museum. The specimens often arrive in dusty, old, newspaper jackets, which although can appear to be historic artefacts themselves, can cause rapid deterioration of the pressed specimens.

First they need a two week stint in the Museum freezer, which eliminates any pests. After this the specimens are carefully restored so that they can be incorporated with the rest of the herbarium.

The specimens are removed from the old papers and re-mounted onto archival quality sheets, along with their original labels and annotations. John Hunnex, the herbarium technician, has provided some unparalleled tuition in plant-mounting, and I have now spent many hours carefully fixing specimens and labels to their new sheets.

Photo showing Sally's hand lifting a specimen onto a new sheet
Re-mounting herbarium sheets

I have also been re-organising the herbariums collection of Centaurea – a group of flowering plants known as the knapweeds, which exhibit striking variation. Just like us, plants can be incredibly variable in appearance, with individuals often displaying features very differently, despite belonging to the same species.

Photo of 3 different flower heads from Centaurea nigra
Variation in Centaurea nigra as observed in specimens from the Museum’s garden

This variation meant that many past natural historians were puzzled by knapweeds, unsure whether to consider them as just one, two or even several species. Over time, they were split up into many different sub-species and variants – the used names often evolved as understanding of the variation changed. Many of the collections Centaurea specimens remain inconsistently named and ordered so I am attempting to re-organise the collection and re-identify the specimens.

To do this first I am putting all the specimens into geographical order, depending on where they were collected within the UK. By doing this I will hopefully be able to unpick some of the natural variation across and within populations of knapweeds, and better understand this complicated group of flowers.

Photo of Sally looking down a light microscope at a herbarium sheet
Hard at work identifying specimens

Sally Hyslop, Identification Trainers for the Future

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