I have been writing a regular Nature Notes column for almost six years, but until now I have avoided talking about one of our most important and difficult plant families – the Grasses (Poaceae).
Grasses are one of our largest plant families; 12,000 species worldwide, with 220 species in the UK. Grasslands cover 40% of the Earth’s land surface, and account for 45% of the calories we consume as humans.
As major civilizations slowly developed (roughly 10,000 years ago), wild grasses with exceptionally large grains were brought into cultivation and have slowly evolved into the food we eat today:
• In China there was Rice.
• In South America there was Maize.
• In Europe within the Fertile Crescent (modern day - Middle East), there was Wheat and Barley.
• And in Africa there was Sorghum and Millet.
Grasses evolved earlier than was originally thought, probably around 82 million years ago. Unlike most other plants that grow from the tip, grasses have their dividing cells at the base of the plant. This means that if shoots are grazed by herbivores or livestock, new shoots will continue to grow from the base.
Many botanists shy away from grasses - they can be difficult to identify. In the first place, they don’t have petals you can count, colours you can categorise or leaves that are easily distinguished. Secondly, they come with a whole new glossary of terms, and finally there are just so many of them.
I think everyone should recognise at least one Grass. I have chosen to highlight one very common species found throughout the UK and northern Europe. It also has a local connection, its name ‘Yorkshire Fog’ (Holcus lanatus).
It is said that Yorkshire Fog was given the name because, from a distance, it resembles the smoke that once billowed from the chimneys of northern factories. This is especially so before the flower head or panicle (inflorescence) fully opens. The hairy stem or culm acts as the ‘chimney’ (see photo).
Next time you are on your travels, and you spot Yorkshire Fog, think to yourself – ‘It is always nice to see a little bit of Yorkshire when you are away from home’.
Even if you are not tempted - to start identifying this complex group of plants, do take time in the coming summer months to take a path through an uncut meadow. As the wind gently moves the sward, sit down, take time to listen and watch the swaying grass - it is beautiful.
www.wharfedale-nats.org
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