Wednesday, 25 April 2012

An introduction to plant botany Part 2

The binomial system
In the previous post we saw that every species has it's own unique name. These names are in Latin because (a dead language) so they won't change overtime due to changes in the language. Local names for plants may also differ between places, or the same name may be used for several different plants. Because nobody actively uses Latin anymore, these names are more or less guaranteed to remain the same.

 Fig 1. C.Linnaeus. 

Linnaeus introduced the binomial system, in which the first part of the name identifies the genus and the second part identifies the species within that genus. For humans it´s:  

genus                   species
Homo                   sapiens

The genus of maple trees is Acer. This genus has a lot of species, including:
Acer saccharum = Sugar maple

Acer rubrum = Black maple
Acer pseudoplatanus = Sycamore maple

Divisions in the plant kingdom
The plant kingdom consists of several divisions, the most “simple” plants are in the moss (Bryophyta), hornwort (Anthocerotophyta) and liverwort (Marchantiophyta) divisions. The plants in these divisions are all non-vascular plants, they lack veins and vessels that move water and nutrients internally. All the plants in this division use spores to reproduce.  

In the clubmosses (Lycopodiophyta) and ferns and horsetails (Pteridophyta) divisions we find plants that are still spore producing plants but do have an vascular system.

Plants in the conifer (Pinophyta), cycad (Cycadophyta), gentum(Gnetophyta) and gingko (Ginkgophyta) divisions use seeds instead of spores for reproduction. The plants in these divisions are called “naked-seed plants”. They are called this way because the egg cells need to be exposed to the air and need pollen to land directly on the surface for fertilization.

Plants that have stamens, pistils and produce seeds that mature in an enclosed ovary, are in the last division of the plant kingdom: that of the flowering plants (Magnoliophyta). Another name for this division you might run into is Angiospermae. This division contains the most plants of all, around 250.000 species. We’ll cover flower characteristics in the next plant botany part.

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