Since 1993 I have recorded the week that each of my ferns has emerged.
Here is a chart showing each taxon and the week of emergence for each year.
Below it is a summary of how many taxa emerged each week, in each year.
I have begun to analyze this data. Here is an older graph of cumulative average emergence dates for 1993 to 2011, and a graph of that average compared with a few interesting years.
Here is a recent comparison of the emergence figures for the first ten years of these readings vs. the last ten years. I was surprised that emergence appears to have become somewhat later. Not what I would expect from global warming.
These are comparisons of the collections of ferns I had in each year, but they were not entirely the same sets of taxa, as some died and some were aquired. I will try the comparison using only those 15 taxa that have persisted for the entire 23 year span. Even so, there have been some discontinuities when I replaced one plant with another of the same taxon, in perhaps a different location.