Equisetaceae

The horsetail family in Belgium:
Depending on the classification, the genus Equisetum (horsetail) belongs within the plant kingdom to its own family, its own order, sometimes its own class, and exceptionally even to its own division! This means this is a quite special little plant which differs from every of the big groups: it does neither have flowers nor needles, it is clearly not a moss, but it is actually not really a fern either… No: a horsetail is simply a horsetail!
The genus Equisetum is considered to be the sole surviving member of a very old group of plants which already populated the Earth long before the arrival of dinosaurs. The group was much more diverse in those days; relatives of today’s horsetail grew as trees and formed the first forests of our planet. We know this thanks to fossil traces, since by looking at our present horsetails and their herbaceous habitus, we could hardly ever imagine that their ancestors were once the lords of the forest.
The 15 to 20 species of Equisetum can be found almost everywhere in the world, mostly in proximity of water. This is due to the fact these are very primitive plants which need water to reproduce; they do not need pollinators, just water. To determine the exact amount of species is not straightforward, because several fertile hybrids between the species are known.
Morphologically, Equisetum species differ only slightly from one another. They consist of a rhizome connecting the visible green parts above ground. Those green parts may remind us of small needles of conifers, they are however no leaves at all but modified stems; the real leaves form a ring at regular interval around the main stem and are rather unimportant for photosynthesis. The spores are produced in terminal “spikes”.
In our region, eight species occur. A long history of medicinal use is especially true for the common horsetail (Equisetum arvense); for horses, if eaten regularly, it may lead to catastrophic consequences. Some species among which the common horsetail – may in some cases become weeds hard to fight against.

The Belgian Herbarium:
The Botanic Garden Meise holds the largest herbarium collection of Belgian plant specimens. Each of these herbarium specimens has a label with valuable information such as the plant’s identification, and when, where, and who collected the plant. These specimens can be used in many domains of research, such as conservation, evolution, ecology and systematics. These data help us to better understand the plants of Belgium, their history and that of people who collected them. There are about 200,000 specimens in the Belgian Herbarium of the Botanic Garden Meise and we want to document them all! These data will then be made available online at www.botanicalcollections.be.

Keywords (Latin):
Belgium, Equisetaceae, Filices, Hortus Botanicus Meise, Botanica.