Ephemerals, or Not? -by Jim Rogala

Mike O’Brien’s blog post on ephemerals contained some lovely photos of plants that flower very early in the year. Although the definition of ephemerals varies, not all of the early flowering species are technically ephemerals according to some experts. In John Curtis’s classic book “Vegetation of Wisconsin”, he defines ephemerals as plants that have leaves and flowers that completely die back by the time the closed tree canopy has full leaf development (i.e., sunlight no longer hits the ground). Curtis lists examples of ephemerals to be trout lilies, squirrel-corn, dutchman’s-breeches, spring-beauty, toothwort, and false rue-anemone. Close to being a true ephemeral is the wild ramps, which has leaves that die back early but that sends up a leaf-less flower stalk in mid-summer. Curtis lists examples of other early blooming species that retain leaves for part of the summer, and therefore are not true ephemerals. These include bloodroot, Jack-in-the-pulpit, wild ginger, cohosh, hepatica, woods phlox, mayapple and trilliums.

There are other growth and blooming strategies to deal with the lack of light under leaf-out periods in the woods. One example is the putty-root orchid that uses late fall, winter, and early spring to photosynthesize in the woods, with leaves retained through the winter. It then flowers as the leaves die back in May.

The leaf of putty-root dying back on May 27

Flowers of the putty-root starting to bloom also on May 27

For prairie and savanna plants, the need to rush the process of the acquiring light to build and replenish energy reserves is unnecessary because they are not under a closed canopy. However, even prairie plants have strategies to maximize the period over which plants bloom. All the early spring flowering species on prairies are short in stature because they don’t have time to build a lot of foliage before flowering. They also will soon become shaded by the plants producing taller foliage. Early blooming prairie species such as pasqueflower, violets, and prairie smoke are good examples. These species largely rely on energy reserves from the previous year to produce flowers. Consider the height of later blooming species such as goldenrods or the mighty silphium species, and you can imagine that flowering can’t happen early in the year.

There are a multitude of strategies that make each species successful in carving out their niche, but certainly you can see that timing of leaf production and flowering play a role in many plant communities.

Jim Rogala

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