ARBORETUM NEWS (NATURALISTSNOTES)

Greene Prairie and Grady Oak Savannas

SUNDAY, MAY 20, 2012

It was a busy Sunday in Madison—graduation, festivals, runs, and many other events—but we still had a good turnout for our walk across the Grady knolls and into Greene prairie.
Early into the walk, we started checking the undersides of milkweed leaves to look for monarch eggs. One of the first leaves I looked at had a little egg that was exactly the right shape and texture—just not quite the right color. (Note: This is foreshadowing later events. Remember this!) We continued along, checking here and there. We found a few more of the same type of eggs, but nothing the right color.
Up on the knoll, we enjoyed the contrasting oranges and blues/purples of hoary pucoon and lupine along with the creamy Baptisia flowers. We saw rock cress—nothing too special, but so elegant and graceful, especially with its long seed pods, characteristic of the mustard family. Off of the knoll, we looked at a cluster of blackberry plants and almost decided that some were black raspberries—but then decided to wait for another opportunity to compare. Not too much later, we decided that they really were all blackberries. We were looking at the stems—blackberries have ridged green stems while black raspberries have round purplish stems. But there were some blackberry stems that really didn’t look all that green or ridged—which threw us off for a while. The flowers of the two plants differ, too. Blackberry has larger petals, and therefore a much showier flower. Black raspberry petals are quite small—they almost look too small for the rest of the structure. In the Grady tract, the black raspberries seemed a little further along in their life cycles than the blackberries. The black raspberry flowers had already given way to small fruits while the blackberry flowers were in full bloom.
In the Greene prairie, there’s phlox in full bloom and the last few flowers of Jacob’s ladder. It seems to me that there’s almost always some orchid in bloom in the Greene prairie and indeed, we admired several clusters of white lady’s slippers. Other flowers in bloom included yellow star grass, blue-eyed grass, bluets, shooting star, Seneca snakeroot, marsh pea, ragwort, golden Alexander and heart-leaved golden Alexander, and yellow pimpernel. With apologies to any flowers I forgot to mention.
On the way back up we checked more milkweed leaves. Then someone spotted a tiny monarch caterpillar, striped yellow, black, and white. That’s when the dots connected—the eggs were monarch eggs, they were just empty monarch eggs!
On the subject of larvae, we saw some spectacular oak galls. I have since learned that these are commonly called oak apple galls. (We were thinking that they should be called something like “spiky lime gall.”) The galls hang down from the branches like apples (or spiky limes) and each contains a wasp larva. We found one that had fallen to the ground and opened it, revealing the larva in a small central compartment.
One last note—as I was scouting on Saturday I saw a pair of sandhill cranes land in the Greene prairie. I tried to spot them again but couldn’t find them. I wonder if they have a nest there? Has anyone else seen them?
Sara Cohen Christopherson, Naturalist

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.