Tom's Blog

Saturday, September 6, 2008

Seed collecting at Goose Pond

For ten years, Kathie and I have been volunteering as seed collectors at Madison Audubon Society's Goose Pond Sanctuary. Today was the "kick off" for seed collecting for the fall. Everyone who turned up were old Goose Pond "hands", and it was almost like a club. (However, new people would be very welcome!)

The June 2008 flooding had brought about some interesting changes at Goose Pond (the pond is now a "lake"). However, the principal seed collecting prairies are fine, and we were able to bring in quite a few seeds. The species collected were: side oats, flowering spurge, Illinois trefoil, and golden Alexanders.

Golden Alexanders (Zizia aureus) is a very fine spring prairie/savanna species, flowering in late May and early June. A member of the carrot family, it has bright yellow seed heads (umbels) which provide lots of color in the late spring/early summer growing season. At present, it is being dwarfed by the summer/early fall members of the tallgrass prairie, making it fairly hard to find. We had to redirect our thinking and look for carrot-like seed heads that were only three foot high (if that, many had fallen down). Some of the heads had already lost their seeds, and we had to be careful to not knock off the seeds of the ones we were collecting. The technique here is to grab together three or four heads, cut them with a clippers, and lower them directly in the seed bucket. Even being careful, it was difficult to get all the seeds in the bucket.

The photo below shows only part of the "catch". To clean the seeds, they will be first run through the "hammer mill" to shake the seeds off, and then pass the milled material through a fairly fine screen.

I was interested to see that although the seed heads were very dry, there were lots of green leaves of Zizia aureus growing close to the ground. Since this plant grows vegetatively in May, where did these fresh leaves come from? A number of the early flowering prairie plants have a second growth phase in the early fall, after days are starting to get shorter. I haven't seen much literature on this phenomenon, but I assume that during this fall growth phase the nutrients produced are translocated to the roots and provide a boost for the following spring. In addition to Zizia, I know that bird's foot violet also has a fall growth spurt.


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