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| A colony of mayapples, Podophyllum peltatum. |
They’re relentless, these mayapples.
Over many years, five plants became ten, then twenty, then fifty.
As their numbers increase, young plants at the boundary of the patch run head-long
into ostrich ferns and wild ginger, themselves trying to gain new ground. The
outcome of their competition is uncertain, but their shared imperative is
clear: Advance.
Mayapples do this using rhizomes (RY-zomes), underground
stems that grow more or less horizontally and produce roots and shoots along
their lengths. In ideal conditions, mayapple rhizomes grow rapidly – up to 20
centimeters, or 8 inches, per year (1).
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| A mayapple rhizome is a horizontal, underground stem. Roots and shoots develop along its length. |
If a colony begins with a single seed and if it successfully grows and reproduces this way, the result is a patch of genetically identical individuals – clones, in other words. In ecological terms, the clones are called ramets, and the genetically distinct population they belong to is a genet.
In a favorable and stable habitat, reproduction by rhizomes
is an advantage. If their genes are suitable for where they’re growing, ramets produce
mature plants faster than seeds. They’re also less expensive. Compared to flowers and fruits, they demand
less of a plant’s energy to create.
If the environment or habitat changes, however, a colony of
clones may not have the right genes to adapt and survive. If they’re all the
same, they would respond similarly to a shift in some variable, such as
temperature. If the change is more than they can handle, the genet may not
survive.
That’s why variety is important. Mixing genes, such as by
cross-pollination between genetically different plants, produces new and
possibly better, more adaptive, combinations. Reshuffling the genetic deck can
be an advantage, so mayapples also produce flowers.
That big-budget task falls to the older ramets. Unlike
younger plants, they have two umbrella-shaped leaves instead of one, and
between them grows a single, white, bowl-shaped flower that blooms in mid to
late spring. It takes some effort and good timing to see it. Although it’s an inch or two across and
somewhat showy, it’s below the leaves and nodding, and it’s spent in a couple
of weeks.
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| Mature mayapple ramets produce a single, white, nodding flower. |
The flowers produce no nectar, but bumblebees and other insects visit them to collect pollen (2). Without pollinators mayapples won’t produce seeds, because they’re mostly self-incompatible – they can’t pollinate themselves, as some plants do if cross-pollination isn’t successful (3).
It’s puzzling, then, that mayapples don’t make nectar. A
sugary sip is a sure draw. It’s another expense, though, and mayapple’s budget seemingly
doesn’t cover it. Instead, the plants may rely on other species to provide the
bait. For example, one study found that mayapple colonies close to
nectar-producing lousewort (Pedularis canadensis) were visited by
pollinators more often. Because it flowers at the same time, lousewort acted
like a magnet, drawing pollinators that would then more frequently visit a
mayapple patch (4).
When fruits are ripe, another challenge arises: What will disperse
the seeds? Box turtles, deer and raccoons are among the animals that eat the
fruits (5, 6). They will deposit the seeds in their feces, but that’s not
always the end of the story. White-footed mice and chipmunks have been observed
picking mayapple seeds out of raccoon dung to eat or cache, and rainwater may
also usher the seeds out of the muck and onto new ground (6).
If the seeds end up in a favorable spot and if conditions
are right for germination, mayapple seedlings emerge. They begin another genet,
a new colony, with an old and familiar habit. The march of the mayapples
resumes.
How to Identify Mayapple
Mayapple’s scientific name, Podophyllum peltatum,
describes the plant’s appearance. Podophyllum comes from Greek words meaning
“foot leaf,” referring to the foot-like shape of the leaf lobes. The name peltatum
refers to the plant’s peltate leaves. They are attached to their petioles
at the center of the blades, like an umbrella or a shield.
For more photographs and tips to identify mayapple, see the Minnesota
Wildflowers page for this species.
Caution
Mayapples are hazardous. Except for ripe fruits, all parts
contain harmful concentrations of podophyllotoxin, a potent compound that can
be absorbed through the skin and digestive tract. Plants are most poisonous
when they are flowering. See Colorado
State University’s Guide
to Poisonous Plants for more information.
References
(1) eFloras
(2022). Published on the Internet http://www.efloras.org [accessed
13 May 2022]. Missouri Botanical Garden, St. Louis, MO & Harvard University
Herbaria, Cambridge, MA.
The eFloras page for mayapple is here.
(2) Mahr, S. Mayapple, Podophyllum
peltatum. Wisconsin Horticulture, Division of Extension, University of
Wisconsin-Madison. Accessed May 17, 2022 at https://hort.extension.wisc.edu/articles/mayapple-podophyllum-peltatum/.
(3) Whisler, SL, and Snow, AA. 1992.
Potential for the loss of self-incompatability in pollen-limited populations of
mayapple (Podophyllum peltatum). American Journal of Botany 79 (11): 1273-1278. https://doi.org/10.2307/2445055; https://www.jstor.org/stable/2445055.
(4) Laverty, TM. (1992). Plant
interactions for pollinator visits: a test of the magnet species effect.
Oecologia 89 (4): 502-508. https://doi.org/10.1007/BF00317156,
https://www.jstor.org/stable/4219917.
(5) Rust RW and Roth RR. 1981. Seed
production and seedling establishment in the Mayapple, Podopyllum peltatum L.
The American Midland Naturalist 105 (1): 51-60. https://doi.org/10.2307/2425009;
https://www.jstor.org/stable/2425009.
(6) Niederhauser EC and Matlack G.
2017. Secondary dispersal of forest herb seeds from raccoon dung: contrasting
service by multiple vectors. Plant Ecology 218 (2): 1135-1147. https://doi.org/10.1007/s11258-017-0748-4.
