Sunday, May 15, 2016
The Korean fir Abies koreana in our garden has been releasing vast amounts of pollen over the last few days.
These are the male, pollen-producing cones near the ends of the branches. Like all conifers it's wind pollinated and the pollen released is quickly diluted in an enormous volume of air, so it tends to be produced in great quantities. If you give the tree a shake it briefly hangs like a yellow cloud in the air.
These are the pollen grains under the microscope, magnified about 80 times.
If you look closely you can see that each pollen grain has two inflated air sacs, which are extensions of the pollen coat. These increase the surface area of the pollen with minimal increase in weight, so enhance its aerial buoyancy.
Click here for more on conifer pollination.
This is where the pollen grains are heading - the new female cone at the top of the tree. Only a few of the pollen grains will successfully complete their journey and fertilise the female ovules, which are arranged in pairs on the upper surface of those whorls of cone scales.
At this time of year they are an attractive shade of purple but by autumn, as they seeds develop, they become brown and then break up through the autumn. Coal tits are particularly partial to the seeds - click here for photographs of them picking the cones apart.