ARBORETUM NEWS (NATURALISTSNOTES)

Arboretum Sampler – Hawks to Hedge Apples

SUNDAY, SEPTEMBER 23, 2012

Sunday’s Arb Sampler tour started with a dramatic appearance of a red-tailed hawk that swooped down off of the Visitor Center, skimming right over a visitor’s head, and off across the parking lot. We then proceeded to take in a lovely sample of fall.
Starting in Curtis prairie, we admired the fall colors of the prairie landscape. I like to think about the ways in which we humans are influenced by plants. For example, think about how our culture’s fall wardrobe colors—rusty oranges, dark yellows, maroons, etc.—mimic the fall landscape. (Why do we think of pastels as “spring colors??” We humans like to think we are in control but it’s fun to think about the many ways in which plants control us!) Many of the season’s flowers are past, but the grasses are glorious and a number of assorted yellow

compass plant


flowers—of compass plant (Silphium lacinatum), sawtooth sunflower (Helianthus grosseserratus), and others—were still in full bloom. Purple asters are out. The gentians in the remnant section of Curtis are done blooming. I had hoped that the cool weather may have preserved a few blooms but we found only the brown remains of their petals.
We headed over to check on Teal pond. There’s a green heron that’s been hanging out there but, alas, not when we stopped in. We did, however, see some mallards and a small turtle. We spent a few silent minutes, taking in the scene.
Then on into Gallistel woods for a quick little loop. Between F4 and F6, we spotted a woodpecker. We thought it was likely a hairy woodpecker (Picoides villosus), judging by the long beak. As we approached the G6 trail T, a red-tailed hawk swooped through, close again, and perched above us on a tree branch. We all tiptoed quietly around the corner to get a better view. The bird allowed us some viewing time and then flew off, joined by another nearby red-tail that we didn’t even notice.
Out in Longenecker, we made a few stops to enjoy fall fun. First stop: an osage orange tree (Maclura pomifera). Its original distribution is thought to be restricted to a portion of Texas, but was introduced far and wide in the last 150ish years. It cattle. Its fruit is a large, green, bumpy ball of a type known as a multiple fruit. It’s basically a conjoined mass of individual fruits. Someone evidently thought it looked like an orange but it is just as brain-ey as it is orange-ey, if you ask me. There’s one in the visitor center on display—you can judge for yourself.

Osage Orange or hedge apple


Squirrels sometimes tear the fruit apart, but there’s no animals that are known to really consume the fruit (and therefore distribute its seeds). The accepted hypothesis is that the fruits were once distributed by an extinct ground sloth or other extinct large mammal.

Second stop: the American chestnut. Now rare, after 100+ years of chestnut blight, only a handful of individual trees exist in Madison.

Squirrels getting chestnuts


The chestnuts develop within an incredibly armored husk that is lined with velvety-soft brown fuzz. The husks are split open now, revealing the velvet. Nuts are hard to find because they are very shriveled and unpalatable-looking nuts that were left behind. Third stop: the seven-son flower tree (Heptacodium miconiodes), in full bloom, fragrant, and covered in bees and other insects. This plant is native to China but survives our WI seasons. Final stop: a native witch hazel (Hammamelis virginiana). This is the latest-flowering of our native plants and buds were just barely beginning to open. After some cool, crisp days, I admit I was a bit relieved to see that the witch hazel wasn’t blooming yet. We still have some time before it’s really autumn.

Sara Christophersen, 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.