Story by Virginia Barlow | Illustrations by Adelaide Tyrol
At the risk of being considered a nit-picking pedant, I repeat: spring ephemerals are not the
same as spring wildflowers. The leaves of spring ephemerals are addicted to light, and sunlight
on the forest floor is at its most intense before trees leaf out. When the canopy closes in May,
ephemerals seem to be unable to adjust and they call it quits. They’ve been called the “fast
food junkies of the forest,” eating as fast as possible because the joint closes early. Somewhat
more scientifically, they’ve been said to lack “photosynthetic plasticity.” The leaves of trout
lily, spring beauty, and toothwort live for about 10 weeks; after that, they wither completely.
True ephemerals grow in rich sites and operate efficiently at low temperatures, their fleshy,
nitrogen-rich leaves allowing for speedy weight gains.
Although these three species decorate the woods with flowers early in spring, other spring
wildflowers whose leaves stay green through most of the summer – the trilliums, bloodroot,
blue cohosh, jack-in-the-pulpit, Canada mayflower, and false Solomon’s seal, for example
– are not spring ephemerals. However short-lived the flowers of these spring wildflowers, the
leaves carry on after the tree canopy closes. Some of these get most of their annual income
early in spring, but they stay in the black, so to speak, throughout the summer, even when
shaded by leafed-out trees.
TROUT LILY, Erythronium americanum
The yellow flowers of this lovely forest lily are common in sugar maple woods, though only
a small percentage of plants flower in any given year. In rich woods, the dusty green and
purple trout-patterned leaves often form a dense carpet that appears just after snowmelt and
completely disappears by mid-June. Yet, in that short interval, plant biomass sometimes more
than triples. An unusually high photosynthetic rate helps, but this species has other things
going for it as well.
A mycorrhizal fungal network that penetrates and connects plant roots in a symbiotic
relationship allows trout lily to engage in an elaborate nutrient give-and-take with sugar
maples, their most common forest companions. In one experiment, scientists planted trout
lilies in a container with sugar maple saplings around the time that the maples unfurled
their leaves and the trout lilies began to fade, and labelled the trout lilies with
radioactive carbon. Seven days later they found that very same carbon in the
leaves of the potted sugar maples. As a control the researchers did the same thing
with yellow birches, a species known to partner with a different fungus, and no
carbon appeared in the birches. The experiment was carried out in reverse
in autumn by labeling the sugar maple leaves the same way, and, you
guessed it: carbon showed up in the corms of the trout lilies.
Why, you might ask, would trout lilies need a carbon boost in autumn? It
turns out that that’s when they grow new roots, and their shoots inch toward
the surface throughout the winter. It’s in autumn that they, along with myriad
soil microbes, absorb nutrients that might otherwise be flushed
away and lost to the forest ecosystem. This winter growth leaves
the trout lilies poised to hit the surface as soon as the snow melts,
allowing the plants to bask in unobstructed sunlight for as long as
possible. Trout lilies treated with a mycorrhiza-killing fungicide grow at
half the rate of normal plants.
Some trout lily colonies are believed to be over 300 years old. The
plants reproduce by ant-dispersed seeds and by bulb offshoots.