Thursday, September 27, 2007

American basswood

This tree isn't growing in my garden, unless you define my garden very broadly, but I wanted to post a picture so people can see what I study for a living. Tilia americana, the American basswood or linden, grows in mesic forests throughout the eastern half of North America. The range may or may not be further divided into multiple species, but in any classification scheme the northern populations are T. americana. Lucy Braun said that the Minnesota populations are the most "pure", untainted by introgression from other tilias. I don't know about that, but the trees in Minnesota forests were immense and beautiful.

Tilia americana, photo from Nerstrand-Big Woods State Park, Minnesota

My dissertation will focus on phylogeny and population genetics of the North American Tilia taxa. Past "splitty" taxonomists found upwards of 20 species, but recent treatments lump them all together as one. I hope that my molecular data will be the tiebreaker. The over-under is 3. Who's in?

Saturday, September 22, 2007


Borrowed from the bintlog: a picture I took today of Aster oolentangiensis, the sky-blue aster, in my garden.

Another native of Illinois, this prairie plant is a prodigious reseeder. I find new volunteers every year and relocate them to other parts of the garden. Like most of my plants, they are very tippy, and when they fall over onto the lawn or into the garden they look like drifts of pale blue snow. Next year I will try to remember to cut some of them back to see if I can make them more stocky.

Yes, the garden is still alive

Wanted to share the first-ever blooms on my bottle gentian, Gentiana andrewsii, an Illinois native.

This is the second year I've had this plant in the ground. The flowers are interesting because the petals never fully open, and only a bumblebee is strong enough to push its way inside to the rich nectar reward. By coevolving this mutualistic relationship, the bumblebee benefits from reduced competition for tasty nectar, and the plant benefits by increasing its chance of pollination. How does this work? If a variety of non-specialist pollinators pollinated bottle gentian, the chances of each of those individuals also visiting another bottle gentian would be lower because they visit everything, but bumblebees learn that bottle gentian nectar is theirs for the taking and will actually seek out other individuals, bringing conspecific pollen along for the ride. This species, like many others, has thus improved its survival odds by tricking an animal into doing its bidding. That is just one reason why plants are so very cool. Their ways are subtle and deceptive, and they can dish out sumptuous rewards or instant death without all the awkward emotional or moral consequences.