Woodland Walk

Indian pipe

Indian pipe

Sunday was a very high-use day at the Arboretum. The parking lots were overflowing. Cameras were snapping left and right. Joggers and walkers and bikers and others were all around. During our tour, I paused to talk with several groups of people who were not respecting (or not aware of) Arboretum rules. Because we all love this amazing resource that is our Arb, please remember:

• dogs (and other pets) are not allowed
• no picnicking
• stay on trails; no off-trail activity
• do not climb trees
• commercial photographers need to purchase a permit

These rules support Arboretum goals of ecological restoration and land management. Please email Molly if you have questions about these rules.

Our 1 p.m. tour was a large group, full of curiosity and ideas. We set out in the native plant gardens behind the visitor center and walked down to check on the witch hazel. Most blooms were still fresh but some were withered. When the last blooms of the latest-flowering native plant are all withered—that’s when you know that it’s really almost winter. Looks like we still have a little while to go.

We walked over to see the Osage orange (Maclura pomifera) in Longenecker. Osage orange (or hedge apple, among other monikers) is a tree that is native to a small region of east Texas and southeast Oklahoma but was planted widely in the Midwest to contain livestock before the use of barbed wire. The tree is thorny and, when planted as a hedge, grows thickly such that it is an effective hedge or fence. This time of year, the tree produces large green brain-like fruits.

We filed quietly through Gallistel Woods, enjoying the fall colors.

As we were about to cross over to Wingra woods, I was excited to come across a cluster of parasitic plants. At the time of encounter, I didn’t think they were the plant known as ghost plant or Indian pipe (Monotropa uniflora) and was trying to remember the name of another common parasitic plant—sometimes called squawroot (Conopholis Americana). After looking back at the photo I took of the plants we saw and some photos online, I realized that we were, after all, looking at ghost plant (Monotropa uniflora) – but that the plants we saw hadn’t yet fully elongated and turned their “heads” down, so their compact and upright form fooled me.

These ghost plants do not produce sugars through photosynthesis but rather obtain photosynthate (= carbs made by photosynthesis) from another plant. They do not, however, obtain photosynthate directly from another plant. It’s trickier than that. They get their sugars using a mycorrhizal fungus as a middleman. The fungus already has a mutualistic relationship with a plant (the plant gets some help with nutrient acquisition and provides carbs for the fungus “in return”). The ghost plant forms a similar association with the fungus but it’s parasitic, not mutualistic—the ghost plant takes the photosynthate from the fungus.

Nearby were some stalks and berries of poison ivy, without leaves, so no warning sign. The berries and stems can also cause rashes. Birds and squirrels will eat the berries, but they are toxic to humans.

The coming weekend looks to be lovely weather for enjoying the outdoors. Come visit – and please help spread the message of good stewardship of our beloved Arb!

Sara Christopherson