Mary Allen
Plant species are, for example, corn, tomato, cork oak, common beech, or alpine edelweiss. The species is the lowest unit when one wants to classify plants logically. The plants of a species can multiply among themselves and thus spread. They also have common properties that, for example, a tomato and a cork tree do not have.
Several plant species with similar characteristics can be combined into genera. Several genera with similar characteristics in turn form families. These can in turn be grouped into orders, classes, and departments. That would be the largest group. So the classification is getting rougher, the plant species is therefore the most accurate classification. In between, there are even finer divisions.
The classification is the same as for the animal species, with one difference: the animal kingdom is divided into different tribes, and the plant kingdom is divided into different departments. The rest is the same. In science, the classification has changed again and again. In the past, plants were classified according to their resemblance. Today, kinship is also determined by genes.
How do we classify plants in everyday life?
In everyday life we classify the plants as we need them: we have flowers to look at. We usually eat berries and fruits raw, often as a snack. We also eat salad raw, but mostly with a sauce and we need cutlery for it. We mostly cook vegetables and rarely eat them raw, for example, carrots.
In the garden centers, too, colloquial language is difficult. Here, the various terms used to classify plants are often used incorrectly. One often speaks of plant species, but actually means a genus. This is the first group above it. For example, there is no “oak” as a plant species. But there is the genus of oaks. These include the species of cork oak, pedunculate oak, holm oak, and many others. But often only an expert can tell the difference.
How are plants classified in biology?
In biology, you see things differently. The apple, for example, is the first blossom and only later a fruit. If you leave lettuce and vegetables in the garden long enough, they will also develop flowers and later seeds. So that’s not good for a precise classification. The biologists have therefore developed a more precise system. They call it “biosystematics” or “taxonomy”.
In biologists, there are four departments in the plant kingdom: the liverworts, the mosses, the hornworts, and the vascular plants. The vascular plants are the best known. Divide them into two subdivisions, wondering if they have seeds or not.
In the subdivision of seed plants, one wonders whether the seeds are enclosed in an ovary. If so, one speaks of the class of flowering plants. There are 226,000 species. This includes most of our flowering plants, i.e. flowers, fruit, berries, deciduous trees, and many others. If the ovary is open, one speaks of the class of nudibranchs. These include the conifers such as fir, spruce, larch, and many others.
In addition to seed plants, there are also plants that reproduce without seeds. This includes the ferns, which reproduce with spores. However, it is not entirely clear in science which plants should also be included in this subdivision.