Marram grass under the microscope

The photograph shows a stained, thin cross section of the leaf of marram grass Ammophila arenaria. 

What follows has been taken from Phil Gates' blog  beyondthhuman eye. 

"Marram Grass is primarily responsible for trapping wind-blown sand and building the dune systems around our coast that are such important wildlife habitats. Marram grass survives in the arid environment of a sand dune by rolling up its leaves during long periods of drought, so that all the leaves’ breathing pores or stomata are inside the rolled leaf, minimising water loss. This cross section of a  rolled leaf has been stained with dyes to show the different cell types within the leaf. The outer surface of the leaf is composed of a layer of thick walled cells, covered with a thick cuticle to resist wind-blown sand abrasion and this layer also acts like a spring, giving the leaf a natural tendency to roll up under drought conditions. The stomata are hidden on the inner surface of the leaf amongst those stubbly hairs near the bottom of those convolutions – which in the whole leaf are actually ridges and furrows that run along the whole length of the leaf. The clusters of thin-walled blue cells at the base (i.e. in the ‘valleys’) of the furrows of the convolutions are responsible for unrolling the leaf – when it rains and the plant takes up water these thin walled cells inflate like balloons, forcing the leaf to unroll. The  scattered structures that look like ‘smiley faces’ with a pair of large ‘eyes’ with a blue open ‘mouth’ – these are the leaf veins that conduct water and sugars along the leaf – they’re the plant’s internal plumbing system."