Plant systematics
There are more than 200,000 plant species on Earth. Down through the centuries, botanists have tried to name and categorize all of them. They want to classify the species in a correct way. This science is called plant systematics. Many botanical gardens display these relationships in a systematic garden. The Hortus has such a garden: the Semicircle.
In the past, botanists studied the external characteristics in order to determine the relationships. This is called classical or morphological systematics. In the early 1990s, a new method of plant systematics was developed: molecular systematics. This method classifies the plants based on the similarities in their genetic material (DNA).
In the 1990s, scientists have managed to analyse the genetic material of most plant families. In 1998, the joint efforts of that research culminated into a publication proposing a new system for the classification of flowering plants, named the Angiosperm Phylogeny Group (APG) system. As researchers continued their studies and knowledge of molecular systematics became more detailed, the APG is continuously being fine-tuned. Currently, researchers are working on a molecular classification of gymnosperms and spore plants as well.
In 2002, the systematic Semicircle was renovated. The Amsterdam Hortus was the first garden in The Netherlands to present molecular systematics in a systematic garden. In 2005 the Hortus Botanicus in Leiden opened their APG based systematic garden. Now, plant enthusiasts can become acquainted with the new molecular classification of the plant kingdom by means of living examples.
The most recent publications that are now used as reference for the taxonomic mapping of the collection of spore plants, gymnosperms and flowering plants, were published in 2011 in the international scientific journal of Phytotaxa, nr. 19. Click on the links below to find these publications:
Systematics of lycophytes and ferns