by Carl Strang
It’s time to update my record of flowering phenology at Mayslake Forest Preserve. Through April, plants were blooming a median of 13 days earlier than in 2009. In May I have an additional 41 species to report. Five of these were new to the list, and so I have no 2009 dates for comparison. These include nannyberry, about which I reported earlier. Other new shrubs are black raspberry, and autumn olive (shown).
I am not sure how I missed a prominent trailside patch of common speedwell last year.
Even more intriguing is this one:
Clearly a member of genus Senecio, this single plant keyed to butterweed. It is blooming close to the center of the preserve, so I am not sure how it got there. Butterweed is not native, and apparently is not commonly encountered in northeast Illinois, though DuPage Forest Preserve District botanist Scott Kobal tells me he has found it much more frequently in recent years.
Returning to the species for which I had flowering dates in 2009, I had to divide them into two groups. I was out of town for significant portions of May, and so found 16 species blooming profusely that had begun in my absences. The dates I was able to record for them certainly were later than their actual first flower dates must have been. The median was 3 days earlier than in 2009, range 15 days earlier to 5 days later.
Of more interest were the 20 species for which my 2010 first flower dates were reasonably close to the actual. There the range was 4-23 days earlier, with a median of 13. At least so far, 2010 flower phenology continues to be significantly ahead of 2009.
Curiously, migrant bird arrivals do not show the same pattern. The 15 species whose May arrival dates I can compare reasonably between years all appeared later in 2010 than in 2009. The range was 3-15 days later, with a median of 8 days. No explanation immediately comes to mind.