June 2016 – Page 2 – My Chicago Botanic Garden

Sharing the Titan Arum Love

Spring is traditionally the season that gardener friends and neighbors share plants. So when we noticed in late May that one of the 13 corpse flowers in the production greenhouse at the Chicago Botanic Garden was showing signs of sending up an inflorescence, we knew it was time to share.

PHOTO: Loading up the titan arum bud in the truck. — We bid a fond farewell to titan arum no. 5 (now dubbed “Persephone”) on May 31, 2016. The titan traveled by truck to its new home at the Garfield Park Conservatory.

Wanting to spread the titan bounty and to make this amazing plant accessible to Chicagoans from all parts of the city, the Garden turned to our friends at the Garfield Park Conservatory.

Titan arums hail from the rainforests of Sumatra, and therefore need the high humidity and controlled warmth of a greenhouse. (Check: the Conservatory’s Jens Jensen-designed greenhouses include an Aroid House with lagoon.) The plants are notoriously slow to reach the flowering stage and unpredictable when they do—careful horticultural monitoring is a must. (Check: we heart horticulturists.) And the Conservatory is located mere steps from Garfield Park’s beautifully renovated Green Line “L” stop, the city’s most central and accessible train line (super check).

Traveling in the city? Take the Green Line directly to the restored Conservatory–Central Park Drive el station. — Traveling in the city? Take the **Green Line** directly to the restored Conservatory–Central Park Drive “L” station.

For the Garden’s horticulture team, it has been a labor of love to raise “titan no. 5” to this stage. Grown from seed sent in 2008 by the University of California Botanical Garden at Berkeley, the plant had developed the largest known corm in the Garden’s collection. When it was repotted in December 2015, the corm weighed in at 48.2 pounds and measured 16 inches wide and 12 inches tall. Through careful propagation and much TLC, the horticulture staff had coaxed this corpse flower toward opening in just eight years—a fairly short time frame in the life cycle of a titan.

Mary Eysenbach, director of conservatories at the Chicago Park District, and her team at the Conservatory were thrilled to accept the gift of a titan arum, especially one nearing its first bloom. Dubbed “Persephone,” the plant was installed in the Aroid House, where it has been happily growing…and growing…among the Chihuly glass sculptures, reaching 69 inches in height by Thursday, June 16.

All signs now point to the corpse flower opening soon: slowing growth, reddening of the spathe, drying of the bracts. (Read more about the life cycle of titan arums on our blog.)

A titan arum, or corpse flower (Amorphophallus titanum) in bloom. — A titan arum’s inflorescence opens for a short time—just a day or two—and emits a powerfully stinky smell for the first few hours, as the female flowers inside put out the call for pollinators.

If you saw Spike or Alice or Sprout at the Chicago Botanic Garden—or heard about “that stinky flower” through the news or social media—you know what a rare, amazing, sensational phenomenon a corpse flower can be. Increasingly rare in the wild, a flowering titan is a sight to behold, and a wonderful way to learn more about the astounding lives of the world’s plants.

We’re proud to share a titan arum with the Garfield Park Conservatory, and encourage everyone to visit, watch, and smell as its inflorescence opens.

Want to see Persephone in person? Take the Green Line directly to Conservatory–Central Park Drive. Follow the titan’s progress @gpconservatory ‪#‎GPCPersephone‬.

60-Second Science: Begone, Buckthorn!

When buckthorn moves in to the ecosystem, it dominates.

Imagine a friend invites you to a dinner party, promising a delicious spread of food and libations. You arrive, excited and hungry, only to find nothing but raw kale, brought by an uninvited guest. Regardless of your feelings about kale, this would be pretty underwhelming. The other guests are obviously disappointed about the monotonous spread. Most people leave, and because most people aren’t eating the kale, the kale continues to dominate the party. Even if someone brought in better foods that more people enjoy, there is no room on the tables. The kale is everywhere!

PHOTO: Buckthorn (Rhamnus cathartica). — Common buckthorn (*Rhamnus cathartica*)

While not a perfect analogy, this anecdote relays the reasons why buckthorn invasion is detrimental to forest ecosystems. The dinner guests are like the other plants and animals that usually live in the woods. They have certain dietary needs, and if those needs cannot be met, they will have to leave and find another place to live. The more one species dominates (kale, or in many local forests, buckthorn) the fewer species can live there, leading to the ecological equivalent of a party that ends at 8:30, just as everyone was arriving. While it may be true that one person at the party really likes kale, it’s hardly fair for the preferences of that person to supersede everyone else’s needs. In the case of buckthorn, many have opposed its removal because that denies robins a berry that they enjoy. However, keeping the buckthorn (which doesn’t belong there in the first place) is like keeping all of the kale on the tables and not allowing for other foods to be served just for that one person. Even more frustrating, the person that likes kale has plenty of other dietary options. Kale isn’t even their favorite food!

To many people, the idea of cutting down trees to help forests grow stronger is counterintuitive. But buckthorn is no ordinary tree. It is an invasive species, meaning that it doesn’t belong in Chicago area forests, and it steals resources from the plants that are supposed to live here. So remember, when you hear people talking about cutting down buckthorn, they are actually doing it to make the habitat healthier and more inclusive in the long term. They are working to replace the kale at the party with better food and drinks, ensuring that all the guests that were invited can have a good time, staying up until sunrise.

Read more about our ongoing buckthorn battle, and see the difference removal makes in restoring an ecosystem.

Bob Sherman is an undergraduate studying environmental science at Northwestern University. His research interests include prairie restoration and how abiotic factors impact prairie and forest ecosystems. He hopes that his research will have a positive impact on ecosystem restoration and management.

Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

Heliconius: The Lovely Longwings

Here at the Chicago Botanic Garden’s Butterflies & Blooms, we have a variety of butterfly species that fall under the genus Heliconius. This fascinating group is commonly referred to as the longwings.

Longwings are native to the tropical and subtropical regions of the New World. This includes South America, Central America, and the southern United States. Florida’s state butterfly, the zebra longwing (Heliconius charithonia), has been found as far north as South Carolina.

Zebra longwing butterfly (Heliconius charithonia) — Zebra longwing butterfly (*Heliconius charithonia*)

Despite their diminutive size, zebra longwings are noted for their long lifespans, which can be several months rather than several days or weeks. This is thanks to their ability to use pollen as a food source. Unlike nectar, pollen is rich in protein, and this healthy diet allows them to remain fertile for a longer period of time.

Mimicry in butterflies illustrated on these plates showing four forms of Heliconius numata, two forms of H. melpomene, and the two corresponding mimicking forms of H. erato. Image by see Source, via Wikimedia Commons. — Mimicry in butterflies illustrated on these plates showing four forms of *Heliconius numata*, two forms of *H. melpomene*, and the two corresponding mimicking forms of *H. erato*. Image by see Source [CC BY 2.5], via Wikimedia Commons.

Heliconians are also known to be very “intelligent” and social insects. They roost together in large groups, respect their elders by giving them the best roosting spots, and even wake each other up in the morning by gently nudging one another. At Butterflies & Blooms, you can usually find them comingling in loose groups called “flutters,” roosting in long rows on our serviceberry trees, or even mating.

Like Darwin’s finches of the Galapagos Islands, the Heliconians have provided evolutionary biologists with a wealth of information and are studied more than any other butterfly. In the Amazon, Heliconians hybridize, form subspecies and local phenotypes, and mimic one another, confounding even the most seasoned lepidopterists.

Longwings have a unique and bizarre mating tactic called pupal mating that is not seen in most butterflies. Males will seek out female pupae and insert their abdomens into the chrysalids, fertilizing the females’ eggs before the butterflies finish emerging from the pupal stage. Scientists are currently studying the evolutionary effects that this tactic may have.

A Heliconius erato male is attracted by pheromones of a female pupa. He waits until she starts to emerge to attempt mating. Photo ©Holger Klee via Flickr. — A *Heliconius erato* male is attracted by pheromones of a female pupa. He waits until she starts to emerge to attempt mating. Photo ©Holger Klee via Flickr.

At Butterflies & Blooms we always have Heliconians flying around. You may find the postman, zebra longwing, Doris longwing, and many others. Ask us where to find them and we’ll point you in the right direction. Until next time, enjoy the gardens and keep your antennae up for future updates.

Prairie Blooms Beckon

It’s time for a visit to the Dixon Prairie to savor late spring flowers and the pollinators visiting these plants.

White wild indigo (Baptisia alba var. macrophylla) — White wild indigo *(Baptisia alba* var. *macrophylla)*

A standout plant, looking almost like a small shrub, is white wild indigo (Baptisia alba). This is the white-flowered cousin to blue wild indigo (Baptisia australis); this plant, not native to the Chicago region, was historically a source for blue dye. Both species are in the pea family. Many prairie plants belong to the pea family; other important families of the prairie are sunflower, sedge, and grass. Queen and worker bumblebees primarily pollinate white wild indigo. Their large size allows them to push down the lower part of the flower (the keel) and thus expose the pollen producing anthers.

A rich palette of blue flowering plants from the Ohio spiderwort (Tradescantia ohiensis) surrounds the white wild indigo plants. A variety of bees and butterflies might be seen visiting these plants, bumblebees being the primary pollinator. Butterflies, in their quest for nectar, will not be rewarded for their visit, however, since Ohio spiderwort doesn’t have nectar.

Spiderwort (Tradescantia 'Sweet Kate') and coneflowers bloom on the Prairie. — Spiderwort *(Tradescantia* ‘Sweet Kate’) and coneflowers bloom on the prairie.

The prairie also currently hosts numbers of white tubular flowers, foxglove beardtongue (Penstemon digitalis). On the lower half of the flower is a large hairy sterile stamen (the part of the flower that produces pollen); perhaps this feature is the origin of the plant’s common name. Pollinators, primarily bees, must work their way past this sterile stamen to reach pollen. This effort increases the likelihood of pollen being deposited on the stigma, the organ that is receptive to pollen. Those willing to observe these flowers for a while might be rewarded with witnessing some territory defending. The male of an introduced bee, the European wool carder bee, with sharp spines on their abdomens, will attack other males who come in the vicinity of the female when she is foraging for nectar.

Just opening on the gravel hill prairie is the pale coneflower (Echinacea pallida). The narrower leaves of this plant distinguish it from the commonly planted purple coneflower (Echinacea purpurea) (sometimes called broad-leaved coneflower). Like other members of the sunflower or aster family, the coneflower has what appears to be a singular flower but is actually a head of many flowers. This species has what are called ray and disc flowers. Some sunflower plants have only disc flowers while others, such as dandelions, only ray flowers. This plant is a preferred nectar plant of both bees and butterflies.

Moving into summer, this palette will change and reveal a new tapestry of grasses and wildflowers. To witness the full bounty of the prairie, a prairie visit should be a weekly affair.

An Insider’s Story from The Hidden Art of Trees

When a massive weeping willow tree fell in the woods near master crafter Mike Jarvi’s studio, he studied it for many weeks before making a first cut.

Then he got out the chain saw.

The tree had stood astride an intermittent stream for nearly 70 years before falling in a storm. As Jarvi hewed into an especially thick area of the trunk, its remarkable grain and age rings were revealed. The fast-growing willow had recorded both floods and ebbs of water in its rings—some remarkably wide, indicating flood years when the tree grew in great leaps, others quite slim, marking years of drought for the water-loving species.

The front view of this massive desk, created from a single willow trunk.

Jarvi cut one massive section from the trunk, envisioning a desk, then cut into that piece for a matching chair that fits neatly into the desk “slot.” Both pieces were hoisted into his shop’s loft to dry…for four years. The chair slab weighed in at 230 pounds when it arrived; four years later, is was down to 130 pounds, having lost 100 pounds of moisture.

On view in The Hidden Art of Trees as desk and chair, the willow and its tree rings—and their recorded history—are visible now for all to see.

The Hidden Art of Trees is on view at the Regenstein Center through August 21, 2016. Admission is free; parking fees apply for nonmembers.