Explore/The Gymnosperms

 

Description

The term Gymnosperm means ‘Naked Seed’ and refers to the fact that rather than being enclosed in an ovary, their seeds are covered in just a papery sheath. Current research suggests that they evolved in the late Carboniferous period some 300 plus million years ago. This means that they evolved before most land-dwelling insects and certainly before bees or other pollinators. Most Gymnosperms therefore are wind pollinated and in areas where they dominate the annual flowering can distribute massive quantities of pollen into the atmosphere. This is a fact well-known to Hay-fever sufferers the world over.

The most well-known group of Gynosperms are the Conifers, or cone-bearing plants. These are generally evergreen woody trees whose foliage is needle-like. Many are drought and cold-adapted forming immense forests particularly in the Boreal regions of the world. They are also economically important, with forests being commercially managed for wood and paper products.

Conifers comprise approximately two thirds of the Gymnosperms at about 600 of the 900 or so species known to be extant. There is also a significant fossil record, including some representatives that have characteristics of both ferns and trees. The next most numerous group are the Cycads with approximately 130 species, then the Gnetales which includes oddities such as Welwitschia. Finally and bringing up the rear with a considerable flourish is Ginkgo biloba which is a living fossil at 270 million years old and has the honour of an entire division to itself.

Taxonomically, the Gynosperms are an uncomfortable fit with the Angiosperms and it has even been postulated that the latter may fall within them. However this is a subject that still requires significant research before it can be satisfactorily resolved Back...

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