A new Belgian flora blooms


In the Flore écologique de Belgique (‘Ecological Flora of Belgium’), which uses current species classification, vegetation and ecological criteria-based identification keys, and simplified technical terms, Prof. Anne-Laure Jacquemart and Assistant Charlotte Descamps, of UCLouvain’s Faculty of Bioengineering, have redesigned a reference volume that offers a powerful, modern tool to students and naturalists.

A flora  is a bible to naturalists – they never leave home without it. Until recently, this dictionary-thick volume weighed heavily in a backpack, which would have been less taxing had it at least been up to date. But no one risked designing a new Belgian flora while the Angiosperm Phylogeny Group, an expert group of botanists who work on plant phylogeny worldwide, were engaged in a profound revision of the classification of plants. No one, that is, until Anne-Laure Jacquemart  and Charlotte Descamps took the bull by the horns, albeit without really grasping the magnitude of the task.

‘This work is based on the fact that the plant classification has been deeply reworked’, Prof. Jacquemart says. ‘The world’s classifications of flowering plants have been in a state of continual revision since 1998. Yet all flora in Belgium have been using the old system’. 

While the past nomenclature was based solely on the morphological characteristics of species, the new one is based in addition on genetic (DNA sequences, chloroplast genes), chemical (particular molecules), ecological (pathogens, insects) and biogeographic (distribution zones) criteria. ‘Changes require rewriting the flora in depth, because some plant families have disappeared, others have been split, requiring the creation of new dichotomous keys to identify species’, Prof. Jacquemart says. ‘Naturalists who work a lot in the field sometimes have trouble with innovation. For Belgium, it’s normally the Meise Botanical Garden which is responsible for publishing this type of guide. But the classifications and nomenclature had not yet been revised [Lambinon and Verloove, 2015] . When Lambinon and Verloove  were asked how long it would take, they replied that it would take several years to propose a brand new book! As a professor, I wasn’t going to wait for my pension to offer a new tool to students, knowing that the old nomenclature has been under continual revision for 20 years!’

1,800 recorded species

For many years UCLouvain students have used a simplified flora designed by several teachers (Bastin et al., 2007 for the most recent edition). It’s a simpler model, but was written according to the old criteria. ‘We realised that this simplified flora was actually not very practical. The list of species was incomplete and its identification criteria posed difficulties. In 2015, to maintain its usability, we first reworked the general key in the form of a leaflet that identified families. Then we restructured the keys that identify genera. Students were delighted, especially as the criteria we chose allowed them to identify plants more easily. Charlotte then suggested designing the entire new flora based on the most recent nomenclature. She was very enthusiastic, even though it was a crazy amount of work!’ Eventually a book was born in August 2018. Editions Erasme printed 1,500 copies. The book identifies approximately 100 plant families, 600 genera, and 1,800 species, including ferns, conifers and flowering plants.

The new flora again covers native species, but also the main invasive cultivated or naturalised exotic species. General keys for families and many genera have thus been rewritten and restructured, sometimes according to species environment and ecology. 

Complementary website

Prof. Jacquemart and Ms Descamps accomplished this titanic work in addition to their usual tasks, supported by volunteers; renowned naturalists, future bioengineering students, and interns met at the Cercle des Naturalistes de Belgique, itself a group of about a dozen botany enthusiasts who helped design keys, redefine criteria, and test the reference volume as it materialised.

At the same time, www.biologievegetale.be was created to offer identification exercises and illustrations. It uses the logic of the flora and offers additional information but does not replace the former, as lists fewer species and operates differently. In 2014, the site was awarded the FNRS Wernaers Prize, which recognises teams who have demonstrated creativity, innovation and relevance in communicating their knowledge, particularly to students.

While Flore écologique de Belgique is now available, the work probably isn’t done. ‘We must have forgotten some things, perhaps not everything is correct or complete’, Prof. Jacquemart says. ‘For the moment, we’re trying to have it tested by naturalists who can put a finger on things that don’t work. It’ll be updated as needed. The goal is in any case achieved: thanks to this volume, students work more quickly and are also more motivated because it’s almost easy to identify plants.’
Anne-Catherine De Bast


A glance at Anne-Laure Jacquemart and Charlotte Descamps's bio


Anne-Laure Jacquemart is a botanist by training and professor of ecology in the Faculty of Bioengineering. Charlotte Descamps is an assistant in the same faculty. Their research is organised around plant reproduction and relationships between plants and pollinators. 

Published on January 15, 2019