The introverted bottle gentian is all hue and no cry. This perennial, currently in brief bloom, displays richly violet, bottle-shaped flowers that never open. The corolla (petals) remains closed even when the flower is ready to receive pollinating insects. The burly bumblebee, consequently, is the plant’s primary pollinator, because it’s able to pry open the petals to get at the nectar and pollen. The petals usually feature five lobes, but they’re difficult to discern because of a taller, interconnecting fringe. Inside, the reproductive structures of the flower are fused together to form a central column. Multiple stems can emerge from the taproot of the plant, which is otherwise unbranched. The upper surfaces of its lance-shaped leaves are dark green and often shiny. Populations of bottle gentian plant are probably declining due to wetlands destruction.

Common Names: bottle gentian, closed gentian

Scientific Name: Gentiana andrewsii

Family: Gentianaceae

Native Status: eastern North America; occasional in northern Illinois

Plant Type: herbaceous perennial

Height: 1–2 feet

Spread: 1–1.5 feet

Flowering Time: late summer–early fall

Flower Color: deep blue, purple

Interest: showy flowers suitable for wild flower, shade or native plant gardens; attracts bumblebees

The yellow giant hyssop brandishes dense, cylindrical flower spikes that resemble a miniature choir of cacti. The spikes emerge atop stout, square, branching stems and measure 4 to 16 inches long, depending on the size and maturity of the plant. Their 1/3-inch-long yellow-green flowers are short-lived, small in comparison to the rest of the plant, and don’t all bloom at the same time. At maturity, each flower is replaced by four one-seeded nutlets. Colonies are often produced from the root systems of yellow giant hyssop, but the plants don’t fare well during summer droughts. Bees, bee flies and butterflies suck nectar from the flowers, though the dense foliage also attracts predatory insects (wasps, spiders, ladybird beetles). Native Americans used the coarsely toothed leaves in compound mixtures to relieve poison ivy rash. Today, new populations are being found in association with oak savanna restoration—a dynamic that also exists on the eastern edge of Nature Boardwalk, where a new black oak savanna is being cultivated.

Common Name: yellow giant hyssop

Scientific Name: Agastache nepetoides

Family: Mint (Lamiaceae)

Native Status: throughout central and eastern North America

Plant Type: herbaceous flowering perennial (forb)

Height: up to 7 feet

Flowering Time: mid-summer to early fall

Flower Color: white to yellow-green

Interest: can be used in perennial gardens, attracts bees and butterflies

Spiders are incredibly diverse, with around 40,000 different species worldwide. Some spiders roam across the ground actively hunting for prey, while others construct complex webs to capture anything unfortunate enough to fly, jump or fall into them.

Researchers at the Urban Wildlife Institute often encounter spiders in the grass or on trees at Nature Boardwalk at Lincoln Park Zoo. During the recent summer months, though, we’ve noticed some of them—such as the grass spider pictured below—making homes in the metal security cases housing our motion-triggered wildlife cameras!

Grass spiders weave sheet-like webs that generally have a small funnel in a corner for them to hide. The web itself is not sticky, so when unsuspecting prey make contact with it the spider charges out and attempts to paralyze them with its venom. We actually interrupted this individual snacking on an earwig when we cracked open the camera case to check its batteries.

While many people run away in fear or roll up newspapers at the sight of spiders, we’ve recently become very interested in their biology and how important they are to ecosystems like Nature Boardwalk.

Consider, for example, the manner in which spiders breathe.

Most spiders have structures called book lungs, which act as their respiration organ. Even though they’re called lungs, they’re very different from our own. Located inside spiders’ abdomens, book lungs resemble a collection of plates and are filled with the spider’s blood (called hemolymph).

Spiders open small valves, called spiracles, on the undersides of their bodies to deliver oxygen to the book lungs. The oxygen then flows into small, copper-rich proteins present in the hemolymph located in the book lungs’ plates. Interestingly, it’s this particular protein that gives spiders’ hemolymph its characteristic bluish-green hue.

If you can get past your arachnophobia, take a look around Nature Boardwalk to see if you can spot any of these tiny predators. You may find they’ve got a leg—or two or eight—up on the competition.

Mason Fidino

Mason Fidino is coordinator of wildlife management in Lincoln Park Zoo's Urban Wildlife Institute.

This attractive prairie grass is a tussock, or bunch, grass: it grows as a singular plant in clumps, tufts or bunches. It displays blue and silver-tinted stems and leaves in the spring that turn to lovely shades of wine-red in fall. In winter, while the stems of other grasses become matted, this grass species’ stems (or culms) remain defiantly upright, and little bluestem can retain its reddish color into spring. Its foliage and seeds also provide a versatile salad bar for many species: the caterpillars of several skippers (which resemble a cross between small moths and small butterflies); grasshoppers; insects (spittlebugs, leafhoppers, beetles); small songbirds (field sparrows, slate-colored juncos); and bison, cattle and other hoofed mammalian herbivores.

Common Name: little bluestem, beard grass

Scientific Name: Schizachyrium scoparium

Family: Poaceae

Native Status: throughout North America

Plant Type: perennial tussock grass

Height: up to 3 feet

Flowering Time: late summer to fall

Flower Color: light blue to tan, brown and wine-red

Interest: important food source for many species; can be used in gardens as an ornamental grass; highly drought-resistant once established

Rising from the ground up to 5 feet, this slender perennial of the mint family resembles an Indian mystic’s rope trick, with erect cord-like stems that delicately sway in the breeze. Blue vervain’s green or red stems are actually squarish and four-angled, terminating in flowering spikes. The spikes are densely crowded with scentless, reddish-blue or violet flowers. The plant’s name is derived from the Celtic ferfaen, from fer (to drive away) and faen (a stone), referring to the plant’s historical use in treating kidney stones in folk medicine. Native Americans used it to treat colds, coughs, fevers and stomach cramps. The plant’s etymology also includes a religious thread. Some of its common names—herb of the cross, herb of grace, holy wort—refer to the legend (disputed by biblical scholars) that the wounds of Jesus were dressed with vervain when he was taken down from the cross. Whatever the legends, it’s undeniably a beautiful late-summer sight at Nature Boardwalk.

Common Name: Blue vervain, Swamp verbena

Scientific Name: Verbena hastata

Family: Verbenaceae

Native Status: throughout North America

Plant Type: herbaceous perennial

Height: up to 5 feet

Flowering Time: mid- to late summer

Flower Color: violet or blue

Interest: Attracts bees, wasps and small butterflies. Various songbirds, including cardinals and several sparrow species, eat the seeds.