Woodland wildflowers: The ephemeral lifestyle of spring beauty

Some might despair that cool temperatures have returned this weekend, but let there be no doubt - SPRING IS HERE! I am not simply stating the obvious that today is the first day of official spring. Spring has been underway for at least two weeks. But if I needed further evidence, I found it under the layer of leaves on the forest floor where woodland ephemeral wildflowers are already making their first appearance if you rake away a few leaves and look closely.

Many spring wildflower species are common in the woodlands of the Credit Valley. The most abundant is the trout lily, which is just starting to emerge through the soil right now, growing from shallow bulbs below or even at the soil surface.

Yellow trout lily that just emerged (2 cm tall) from the ground under last fall's leaves (March 19, 2016)

In another week the characteristically blotched leaves will be clearly visible.

And then the following week a select few plants will produce their six petaled blooms. There are two species of these trout lilies, a common species that is yellow (Erythronium rostratum) and an uncommon one that is white (E. albidum). 

White trout lily (E. albidum), which is uncommon in Ontario but fairly common in the Credit Valley

There are other plants that have just emerged and will flower in the next two weeks. On a south facing slope I found a patch of Virginia Spring Beauty (Claytonia virginica), with its narrow leaves and flower buds that will open next week.

Virginia Spring Beauty (C. virginica), with a cluster of developing flowers (March 19, 2016)

Nearby a rue anemone (Thalictrum thalictroides) plant has just emerged from the soil.

A wee little Rue Anemone (Thalictrum thalictroides) emerging from the soil, just 2 cm tall

I realize it doesn't look like much just yet, but give it another week or two and these beautiful flowers will be out.

Rue Anemone, by Derek Ramsey (cc) https://en.wikipedia.org/wiki/Thalictrum_thalictroides#/
media/File:Rue_Anemone_Thalictrum_thalictroides_Flower_2479px.jpg

On a nearby slope in the Credit Valley is Bloodroot (Sanguinaria canadensis) starting to poke through the soil; its large white blooms will appear within a week.

Bloodroot (S. canadensis) on the forest floor of the Credit Valley (April 2015)

I haven't spotted any evidence of the trilliums, solomon's seal, mayapple or wood lily, but they will make their first appearance in early-April.

For many of these wildflower species their existence is a short one, hence the name "ephemerals". Let me correct myself, their visible existence is ephemeral, but they can in fact live for many many years below the soil as bulbs and tubers, emerging each year for just a few weeks. They emerge from the soil after the snow melts, produce leaves, flowers and fruits, and then as the trees leaf out, they vanish with almost no trace. These plants have evolved a specialized lifestyle that takes advantage of those few weeks that are warm enough for growth and the first emerging pollinators. 

Why don't the wildflowers stick around longer on the forest floor? It all comes down to the balance between the benefit of leaves and flowers and the costs of maintaining them. The function of leaves is to produce energy from sunlight through the process of photosynthesis. There is a lot of sunlight hitting the forest floor right now, enough to produce leaves, flowers, fruits and even a little extra to save away in underground storage structures for next year. When the tree's leaves come out, the light hitting the forest floor drops dramatically. Maintaining a leaf is costly because it requires the maintenance of cellular processes (e.g., ATP synthesis), the production of defences, the replacement of old or lost tissue, and the list goes on. In the simplest of terms, the calculation of BENEFITS-COSTS goes from positive in the early spring before the trees leaf out, to negative once the canopy closes. It is this simple equation, not to mention the underlying complex cellular processes, physiology, evolution and ecology, that have driven the beauty of spring wildflowers's to an ephemeral lifestyle.

Enjoy these plants while while they last this spring. The best viewing will start late March until mid-April this year.