How the Blue Jay Plants an Ecosystem

by Gillian Harris, Bloomington, Indiana

One of the greatest pleasures of living in southern Indiana is wandering our oak-hickory forests in autumn. On a recent outing to a Sycamore Land Trust conservation easement (https://sycamorelandtrust.org/), a small group of us followed environmental education director Shane Gibson through a stand of stately oak trees. We shuffled through the tawny leaf litter, kicking up the autumn aromas of tannin, fungus and humus-in-the-making.

The nasal screams of blue jays echoed through the surrounding woods, so familiar we paid them little attention. We paused now and then to admire the trees and wonder how old they were, as this, like most of our upland forests, was once marginal farmland, abandoned during the Great Depression. Now these oaks have reclaimed the slopes and creek bottoms, just as they once followed the retreating glaciers northward, increasing their range dramatically--and quickly, for a tree with such large, heavy seeds.

We marveled at the plethora of white oak seedlings on the forest floor, dropped directly below the parent tree in a recent mast year (when oaks produce more acorns than can be consumed by the hordes of animals that relish them). Yet even though these seeds had germinated, few of the seedlings will survive into sapling-hood. They will fail to thrive in the lack of sunlight here under the forest canopy.

Acorns, of course, have evolved dense, lipid-rich nut-meats that enlist more effectual agents of dispersal than gravity--most famously the tree squirrel, that icon of autumn nut-gathering and burying. These mammals (and the chipmunks whose alarm calls have been set off by our crashing through the fallen leaves) disperse acorns in the forest as they pile up the seeds in their underground larders.

But what if an oak tree could recruit an even more effective courier, one that moved thousands of acorns every autumn, diligently transporting them beyond the woods of origin—and then stored them under conditions optimal for successful germination and growth into sturdy saplings, and eventually into mature trees?

The JEER-JEER of the jay is such an intrinsic part of the oak forest because the blue jay is the champion mover of acorns. The jay harvests and caches vast numbers of acorns every autumn, and was likely the expediter of the postglacial oak surge northwards, lending wings to the trees’ gravity-bound seeds. The jay even possesses a special adaptation for their conveyance: an expandable crop that serves as a cargo bay, elastic enough to hold several acorns.

Photo by Jake Dingel http://www.ebird.org

Harvesting, transporting and storing seeds uses a lot of energy, so the jay quality-tests each acorn by sight and heft to determine if it’s worth swallowing into its hold. Even loaded with prime acorns, and carrying 1 or 2 more in its bill, the jay, a strong flier, can transport its goods a significant distance from the parent tree. Unlike squirrels, which are loath to venture across clearings, the blue jay readily traverses our fragmented landscape.

Photo by Don Freiday http://freidaybird.blogspot.com

The jay also distributes its acorns broadly throughout this landscape. Using a technique called “scatter hoarding,” the jay has multiple cache sites, usually in edge habitats or small clearings, with multiple cache holes at each site. Within each hole it regurgitates and tucks in just one to a few acorns, and further protects and conceals them with leaves or moss. Scatter hoarding helps ensure the acorns’ winter survival, making them less prone to rot or wholesale depredation by pilfering animals. Blue jays, with their Crow family smarts, remember these highly dispersed caches throughout winter, often using landmarks as guideposts. Some stored acorns are inevitably left uneaten, of course, especially in a mast year.

Come spring, what happens to a high-quality and thus highly-viable acorn, pushed into the earth—effectively planted-- and mulched? It germinates, and because it was cached in a relatively open and sunlit area, away from the competition of other seedlings, saplings or large trees, it has a great chance of growing into a mature, acorn-bearing oak, and contributing to a new oak-hickory ecosystem.

Oaks are host plants to an extraordinary number of cats, including these 3 wonders.

Checker-fringed Prominent, Schizura ipomoeae (top);

Funerary Dagger Moth, Acronicta funeralis (middle);

Spiny Oak Slug, Euclea delphinii, (bottom).

I may not live at my current home long enough to witness the oak trees I’ve planted produce acorns or attain the size of those in the conservation woods, but my 4-foot-tall white oak sapling hosted some extraordinary caterpillars this summer. Throughout its life, an oak is the ultimate giving tree, supporting more wildlife than any other plant, providing food and shelter for an amazing number of birds, mammals, and insects (500+ caterpillar species alone!), creating habitat for wildflowers and mushrooms, adding its tint to the autumn landscape through which we humans love to ramble.

The harsh call of the jay may not be melodious, but to my ears it is sweet; it evokes autumn in the incomparable oak forest—brought to us all by the blue jay.

Blue Jay Note Card

©Gillian Harris

An earlier version of this column was published in my monthly (more or less) column, "The Wild Garden," Bloomington Herald-Times November 2016.

Skunk, Jacks & Dragons: The Curious Arum Family

Jack-in-the-Pulpit (Arisaema triphyllum) unfurling in April.

As July moved into August of 2016, gargantuan Titan Arums were blooming all around the U.S.—in botanical gardens and greenhouses, of course; this peculiar plant, also charmingly called Corpse Flower, is native to Sumatra. In my hometown of Bloomington, the Indiana University greenhouse live-streamed the blossoming of its own titan, “Wally” and visitors queued up to see this rare event, as well as to get a whiff of the flowers' rotten-meat aroma.

Although not as dramatic as their titanic tropical cousin, our Indiana Arums are fascinating their own right. They all share the curious inflorescence (flower head) characteristic of the Arum family, comprised of spadix (the fleshy central spike on which flowers grow) and spathe (the leaf-like structure that emerges from the shoot below the spadix, and partially encloses it like a hooded cowl).

One function of the spathe-and-spadix set-up is to generate heat. The Skunk Cabbage, emerging in wetlands as early as February, is capable of thermoregulation, typically the domain of mammals: through cellular respiration its egg-shaped spadix heats up, and the surrounding spathe acts as an insulator, raising the inner temperature of the inflorescence up to 70 degrees Fahrenheit and allowing the plant to melt its way through snow and ice.

Skunk Cabbage (Symplocarpus foetidus) is able to bloom as early as February due to its ability to generate its own heat.

This toasty temperature keeps the flowers from freezing, and also wafts the Skunk Cabbage’s fetid odor about, drawing pollinators—mostly flies--into the spathe. Honey bees also visit the flowers, procuring from them an important early source of pollen. The warmth inside the spathe attracts the bees and helps them maintain enough body heat and energy to fly from one plant to another, and finally back to their hive.

Skunk Cabbage is not readily available for growing in a garden setting, but two arums that are especially abundant in the forests of southern Indiana make wonderful, carefree garden plants. They merely require light shade and moist soil rich in organic matter to thrive. Jack-in-the-Pulpit is well known for its whimsical inflorescence, the usual Arum arrangement of spadix (Jack) and spathe (the pulpit). Green Dragon also has spathe and spadix, but unlike Jack--a blunt spike peeking from beneath the spathe’s hood--the Dragon’s spadix is long and tapered, extending far beyond the spathe.

Jack-in-the-Pulpit (Arisaema triphyllum).

Green Dragon (Arisaema dracontium).

At the base of the spadix column are clustered tiny flowers—sexual parts only, without extraneous petals, sepals or nectaries. The plants don’t contribute much in the way of bright blooms to the landscape: the Jack’s inflorescence ranges in color from cream to green to dark maroon, while the Dragon’s is greenish-white. In larger plants the spathes are often hidden beneath the leaves, but these unique compound leaves, which remain into late summer, add great interest and texture to the garden.

Green Dragon (Arisaema dracontium).

What insects are lured into subtle, hidden flowers, enticed by an aroma of mushrooms-- with perhaps a soupçon of warm decay? Don’t expect those glamour pollinators, the bees and butterflies, to show up; indeed, you may never even see the insects that make reproduction happen for these two Arums--they are the unassuming, unsung pollinators: tiny flies, thrips, springtails and fungus gnats.

These wee insects don’t even benefit from their efforts. They crawl down into the spathe expecting to find fungus or decaying matter upon which to dine or lay eggs, and fumble around the flowers clustered at the bottom, thereby picking up or depositing pollen. They may then escape the spathe of a male plant through a small aperture at the bottom, but from a female inflorescence, there is sadly no exit.

And so to another curious feature of Jacks and Dragons: they may be male, female, or both, and can control which gender they express. It takes about 5 years for a plant to produce flowers after it germinates, and while it is still small, it produces only male flowers. If conditions are favorable and it continues to increase in size every year, it will eventually transition to female flowers, which require a greater investment of energy. Both male and female flowers may be found together on Green Dragon, but Jacks usually transition completely between one and the other. Gender is reversible as well: in times of stress--drought, for instance-- a female plant can revert back to being male.

Jack-in-the-Pulpit fruits, autumn.

The female plants of Jack-in-the-Pulpit and Green Dragon can be quite impressively robust, standing up to 2 feet tall. Offset corms send up smaller plants below the mother, and cormlets may be divided from the parent and transplanted in late autumn. The fruit heads--clutches of scarlet berries, revealed as the spathe and leaves die back--lend vibrant color to the garden in fall. The fruits are consumed by birds, but all parts of the raw plant, suffused with needlelike crystals of Calcium oxalate, are toxic to mammals. The fruits may be broken apart and dispersed throughout the garden. A generous blanket of leaf mould will keep the seeds from drying out over winter and foster moisture retention in the soil.

A version of this article originally appeared in my monthly (more or less) column "The Wild Garden," in the Bloomington Herald-Times (4 August 2016).

Trilliums: Sweet Whites and "Aromatic" Reds

No spring shade garden is complete, in my estimation, without trilliums and their distinctive triads of leaves, sepals and petals. Our native Indiana trilliums are easy to grow, as long as we provide for them a setting similar to the woodlands in which they naturally occur, with seasonal moisture, shade in summer and a well-drained soil rich in organic matter.

Trilliums are available to buy online and at a few nurseries, but please make sure they haven’t been collected in the wild. Growing trilliums from seed requires patience, as a plant started thus takes five or more years to flower. After a mature trillium goes dormant in late summer, its rhizome may be divided for swifter propagation , but the laid-back gardener may be content to let ants do all the work of dispersal and propagation. Ants harvest the trillium seeds for their nutritious fatty appendages called eliasomes. The ants carry the seeds underground, partake of the attached food, and leave the remaining seeds-- effectively planting them. So give credit to the lowly ant next time you admire a forest full of wildflowers, and also to the flowering plants that have evolved such ingenious methods for both pollination and dispersal.

Our Indiana trilliums are generally either white or red. The impressive Great White or Large-flowered Trillium is perhaps the best-loved of all eastern trilliums. It holds its large ruffle-edged blossom above the leaves on a flower stem--or pedicel--and can occur in stunning massed displays. As it ages, the white flower takes on a rosy hue. This trillium, the Ohio state wildflower, is uncommon in the wilds of Indiana, and is found mostly in the northeastern counties, although it is also present in Brown County State Park.

One of our earliest local wildflowers (appearing in late February), is the diminutive but hardy snow trillium, a specialist of limestone cliffs. It can be quite showy with its pedicelate white flower, leathery blue-green leaves and reddish stem. The restricted habitat of this dwarf species makes it more challenging to grow, but according to Fred Case in his invaluable book Trilliums, it is an “outstanding rock garden plant, . . .easy to cultivate if given limestone soil.”

Two other white trilliums are less showy, holding their stemmed flowers beneath the leaves: Nodding Trillium is extremely rare, found only in the lake counties of northwest Indiana, but the rather unfortunately-named Drooping Trillium occurs in rich calcareous woodlands throughout the state—indeed, Indiana is virtually the epicenter for this common Midwestern species’ range. Despite its name, this trillium is not droopy but can be quite large and robust, with a lovely creamy –white flower that is sometimes held above the leaf plane. In a few wild populations, the petals are deep rose, and the these blooms are quite striking with their contrasting creamy-white pistils. Drooping Trillium is especially attractive when massed on hillsides, where its flowers are more visible from below.

The white-flowered trilliums are pollinated by bees and butterflies. Their odor is pleasant or mild. In contrast are the red trilliums, including the aptly-named Stinking Benjamin (T. erectum), which cater to carrion flies, beetles and gnats with their deep red color and wet-dog aroma. Stinking Benjamin, or simply Red Trillium, prefers acidic soils and is known from only a few locations in Indiana. Its stemmed flower may be erect or slightly nodding. In the Great Smoky Mountains a white or “sweet” form is quite common.

Stinking Benjamin (T. erectum), left, and the white form Sweet Trillium, right.

Scott Detwiler (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

The two red trilliums most familiar to residents throughout Indiana are less smelly and also less showy, with stemless flowers that sit atop the leaves. Rather than spreading to present a landing platform for pollinators, the petals remain upright around the ovary and stamen, inviting insects that savor carrion to crawl around inside.

Recurved, or Prairie Trillium (T. recurvatum).

More (above) and less (below) mottled individuals of Toadshade,

or Sessile Trillium (T. sessile).

Both of these common red trilliums have mottled leaves as well as upright petals, but the differences between the two species are quite apparent if you happen to catch them growing side-by-side. The Prairie or Purple Trillium is a tall slender fellow, with sepals that point down—or recurve-- between each leaf; indeed, a more accurate name for this species is Recurved Trillium (although I rather like the deliciously lurid old folk name “Bloody Butcher”). The Sessile Trillium, on the other hand, is short and squat, with sepals spread out above the leaves. Sessile Trillium is also known as Toadshade, a more fanciful name that is just as diagnostic as “sessile”, which refers to the stemless nature of the flower; after all, this trillium does grow low enough to the ground to shade a hot and thirsty toad.

The flowers of these two trilliums may vary in hue: from vibrant magenta to dull maroon, and even greenish-gold. My favorite Indiana trillium? An individual Recurved or “Purple” Trillium I visit in the wild each year--to admire its pure yellow flower.