Sunday, February 28, 2010
Nothing to sneeze at - yet.
There was some worrying in the media that winter Olympic athletes would be suffering from hay fever at the Vancouver games. The culprit? Alnus rubra, Red alder. The catkins of this member of the Betulaceae (birches and relatives) start to open in February, and continue producing pollen throughout the spring. It was feared that alder pollen would torment athletes, who have the added issue of having to be careful about what drugs they might take to reduce symptoms.
I haven't heard anything more about pollen since the games began. I checked today's red alder pollen count. 12 grains per cubic meter (rated as low).
Female catkins are pollinated now, but fertilization is delayed for 8 weeks or so. The pollen tube grows intermittently, synchronized with the development of the ovary and its ovules. Neat.
The female catkin continues developing through the summer, and seeds are shed from between bracts in the fall and winter, resulting in the small, pinecone-like structures above. In the background and all around, this year's catkins, some ripe, others not quite, are carrying on. So look out.