Virtual Museum of Canada
Jardin botanique de Montréal 
Centre for Forest Research

A hair in your soup

The leaves may also be covered, to a greater or lesser degree, in tiny hairs. In dry climes, these hairs help the leaf surround itself with a protective layer of moisture. Then, when the stomata (A minute epidermal pore in a leaf or stem through which gases and water vapor can pass. ) open, they'll lose less water by transpiration (Loss of water vapor at the leaf surface.), because the layer of air directly touching the leaf is moister than the ambient air.

Since many insects find leaves extremely tasty, the tree may also use this strategy to try and fend off bugs. A deer wouldn't be fazed, but an insect with a much smaller mouth wouldn't find these hairs at all appetizing! One hair in your soup is unpleasant, but a whole wig?? Yuck!


Electron microscopy photo of the hairs on a black walnut (Juglans nigra) leaf
Juglans nigra
© Darmouth College (Louisa Howard )
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