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Grass Identification
Jean Turner
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Introduction to Grasses and their Classification

The flowers of grasses are important for identification.

Grasses are the largest and most important family of the flowering plants. They provide man and his domestic animals with the main necessities of life, they add diversity to the landscape and stability to
the ground surface; they have ornamental and amenity value. (More here)

There are 620 genera and 10,000 species in the world, of which there are only 54 genera and 160 species indigenous to or naturalized in Britain.

Classification and Structure

Because Grasses, Sedges and Rushes are very similar to each other in some respects, it may be useful to point out their similarities and differences.
Insect pollinated flowers are usually brightly coloured and often scented They are all flowering plants. This means they all have their seeds enclosed in ovaries, which are surrounded by bracts (modified leaves, associated with flowers).

In those flowering plants whose seeds are produced as a result of pollination by insects, the bracts (also known in many cases as petals) are often large, brightly coloured and sometimes perfumed. These petals are used to attract insects (left).

Grasses, Sedges and Rushes

A grass inflorescence with stamens protruding to release their pollen on the wind. Grasses, sedges and rushes are wind pollinated. As wind is used to carry pollen from the male to the female part of the flower, the flower has no need of showy petals and these are often reduced or absent.

Other features then become important, such as having very light pollen which can be easily blown by the wind, and very feathery, prominent stigmas which can catch the pollen easily. 



Left: Grass flower head with stamens hanging out to release their pollen into the wind.