Fields and forests may come to mind when you think about PEI’s wildflowers, but our coastlines have beautiful flowering plants you may have never seen or even heard of. Here’s one example: Sea Milkwort (Lysimachia maritima, formerly Glaux maritima).
Life on the coast is tough for plants. There are daily and storm tides, dry and salty conditions, temperature extremes, and often little organic matter in the sandy soil. Like most plants that make a living here, Sea Milkwort has some useful adaptations.
Thick, fleshy leaves store fresh water and reduce water loss under the hot summer sun. Spongy tissue (called ‘aerenchyma’) stores oxygen and carbon dioxide allowing the plant to ‘breathe’ under tidal flooding. Specialized glands on the leaves pump excess salt out of the plant to prevent cell damage. Low growth avoids damage from wind. And Sea Milkwort forms relationships with fungi in the soil that provide nutrients in exchange for sugars the plant makes via photosynthesis. This plant is so specialized that it won’t thrive in less saline, more plant-friendly habitats.
Sea Milkwort isn’t considered edible, although Indigenous people of Canada’s west coast used the roots as a sleep aid. It does resemble an edible and delicious beach plant called Seabeach Sandwort (Honckenya peploides), but the leaves tell them apart. Seabeach Sandwort has larger, sharply-pointed, opposite leaves arranged in strict rows along the stem, giving it a distinctive, orderly look when viewed from above. I think of Seabeach Sandwort like a soldier standing at attention, whereas Sea Milkwort has a more relaxed appearance.
Sea Milkwort is common on PEI and can be found on sandy shores and in the lower edges of salt marshes. It spreads vegetatively and so often grows in conspicuous patches that really stand out when in flower in late June and July. Although these lovely flowers look like they have five pink petals, they have no petals at all. Botanically, those are petal-like sepals: structures that protected the flower bud before it matured.
Too often, we equate biodiversity with species number and apply a ‘more is better’ approach. That’s not how nature works. Coastal ecosystems are among our most important, but often host relatively few – though highly specialized – species of plants. They are also some of the least disturbed habitats we have and are true examples of PEI untamed!