The sun was hot as I sat on a bench outside the Effigy Mounds
National Monument Visitor Center to put on my hiking boots. Entering the woods,
though, the cool shade enveloped me. The air was sweet and buzzing with life. After
a few deep breaths to enjoy the welcome change in the microclimate, I began by
striding up the trail with purpose.
I didn’t get very far. Rosy columbine flowers glowed in the
sunflecks. Neon orange orioles chased each other through the canopy. Both
purple and yellow violets lined the trail, while may apples, wood anemone,
false rue anemone, sweet William, and large flowering bellwort carpeted the
forest floor. A big, fuzzy bumble bee queen investigated hollows in the leaves,
perhaps still searching for the perfect spot for her nest.
Many spring flowers contain both male and female parts on the same flower.
They also use bright colors and sweet smells to lure in a certain set of pollinators.
Jack-in-the-pulpit goes on a different route.
Calcium-rich limestone bedrock poked through black soil on
this river bluff, and the canopy of maple, basswood, and hickory, attested to
the richness of this woods. The calls of warblers, vireos, and a jumble of
other birds floated out over the Mississippi River, which shone like a beacon
on the migratory highway. The place was brilliantly, vibrantly, alive.
A patch of large jack-in-the-pulpit leaves caught my
attention, and I stopped to capture a photo. These unusual flowers don’t have
colorful, silky petals and a sweet smell like the others I’d examined that day.
They aren’t crafted to attract bees (the pollinators at the forefront of my
mind lately); they summon less flashy insects to do their pollen transport.
The outer part of the flower looks like a narrow pouch with a
graceful rain awning, or an old fashioned church pulpit. Often the
pulpits—known to botanists as the spathe—are green with purplish-brown stripes.
This combination of colors, along with a mushroom-like odor, attracts fungus
gnats. I wrote about these tiny cousins of mosquitoes a couple years ago when
they swarmed my window screens in the fall. There are many species, and some
must like to climb down inside the stinky, striped, spathe of an odd flower.
Inside the spathe lives the preacher Jack. His part is played
by the spadix—the spike that pokes up out of the pulpit structure. At the base
of the spadix are tiny flowers, protected from rain by the curving hood of the
spathe. Jack-in-the-pulpits must be at least three years old before they have
enough energy to produce anything except leaves. In poorer soils it may take
longer. After mustering enough resources and storing them in an underground
corm, the plant begins to create male (staminate) flowers.
Similar to the slippery trap of a pitcher plant leaf, gnats
tend to be lured down inside the jack-in-the-pulpit flower and then struggle to
climb back out on the slick sides. Scurrying around the bottom in a panic, they
pick up pollen from the flowers at the base of the spadix, and finally exit
through a tiny escape hatch, carrying the pollen with them.
Jack-in-the-pulpits require cross pollination for seeds to
form, so the plant hopes that the little fungus gnat will fall into a pulpit
with female flowers next. Scurrying around in panic once again, the gnat
transfers the pollen to the stigmas on the female flowers. There isn’t an
escape hatch in these jack-in-the-pulpits, though, and the gnats generally meet
their demise in this beautiful, stained glass tomb. If they’ve done their job
(in the plant’s view, at least), a cluster of green berries will be ripen to
red by late summer.
The unusual flowers of jack-in-the-pulpit develop over
time from having all male parts to all female parts.
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What fascinates me about Jack is his transition over time.
Young jack-in-the-pulpits with few stored resources are male, with staminate
flowers. They only have enough energy to produce pollen. Over time, with ample
nutrition, the plant increases in size both above and below ground. Female (carpellate)
flowers start to appear on the spadix below the staminate flowers. Over the
course of several years, as long as it continues to accumulate enough
resources, more and more carpellate flowers appear until the plant is entirely
female. If soil is poor or the habitat otherwise unfavorable, then the plant
may control its resources output by continuing to produce only staminate
flowers, and thus avoid the expense of growing berries.
Another bumble bee buzzed by as I finished taking my photos
of this curious plant. Lately I’ve been focused on bees and the flashy flowers
they pollinate. Jack-in-the-pulpits are a good reminder that everyone’s journey
is different. They choose fungus over fragrance. They don’t need bees or bright
colors. Their pollinators aren’t charismatic, but they do the trick. Their
gender can change over time. These differences are a good thing. Even though
they are neither sweet nor buzzing, jack-in-the-pulpits are a fascinating
citizen of these woods.
Special Note: Emily’s book, Natural
Connections: Exploring Northwoods Nature through Science and Your Senses is
here! Order your copy at http://cablemuseum.org/natural-connections-book/.
For 50 years, the Cable Natural History Museum has served to
connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit:
“Bee Amazed!” is open.