Here on the coast of British Columbia pollen can start as early as the end of February and last as long as the end of September putting hay fever sufferers at its mercy. Pollen producing plants are all around us and trees are one of the most prolific offenders. The Red Alder (Alnus rubra) brings the first pollen spores by the end of February with a burst of flowers or more accurately called Catkins and carries on until mid march. The catkins appear before the leaves do and are made up of separate clusters of male and female catkins on one tree. Female catkins are only about 2 centimeters in length and not as noticeable as their male counterparts which can be 5 to 12 centimeters in length.
Above is a close up on one of the male catkin from an Alnus rubra (red alder). Each of the long, cylindrical catkin are composed of a complex structure consisting of roughly 120 individual flowers and 480 pollen producing stamens. They produce thousands of pollen grains which are dispersed by wind making it a hit or miss as they drift through the neighboring alder trees hoping to be caught by one of the stigma or pollen receptors on a female catkin. Once the male has released its pollen it withers and falls to the ground.
Above are the ripe female catkins that have turned into a woody 'false cone'. In the autumn the scales open and the seeds are released to be scattered by the wind and water. The empty false cones can hang on the tree for several more years which makes recognizing an Alder (Alnus) easy. The next time you go out for a nature walk keep your eyes open for these easy to spot catkins!!
