Oxalis

Day 156: This is not a shamrock, and I'm Scottish, but hey, I can wish you a happy St. Patrick's Day! This, my friends, is Oxalis oregana, not at all related to the true "shamrock" clover which makes Ireland so green. In fact, there is some debate over which Trifolium species (clover) is actually the shamrock of Ireland, Trifolium dubium or T. repens, both of which grow in profusion there. The confusion began when an English botanist claimed that Oxalis acetosella (Wood Sorrel) was the "true" shamrock back in the first half of the 19th century. Why he made the assertion is uncertain, but the myth was born in that moment. Today, we see pots of "shamrocks" in greenhouses and garden departments; some are green, some maroon, some marked with both colours, joyously perpetuating the misconception. Tell a lie often enough, and you'll find that people come to believe it. Sometimes, you may even believe it yourself, so let's set the record straight. Oxalis may have three leaves, but it's only a sham clover.

Should Be A No-Brainer

Day 165: Believe it or not, the majority of people I meet on the trail cannot tell these two plants apart. It should be a no-brainer. One has four petals, the other five. One has shamrock-shaped leaves, the other a small compound leaf with three parts. Yes, they both are whitish (in some cases verging on pink or lavender), the petals of both exhibit darker purple lines, and they emerge at roughly the same time in the spring and enjoy the same types of habitat. The three ladies I met on the South Swofford Trail a few days ago asked me,"What are the little pink flowers?" When I replied, "Which ones?" they could only say, "The ones we've seen growing beside the trail today." Since we were standing in an area where Cardamine substantially outnumbered specimens of Oxalis, it took a little backtracking before I could point out the differences. While some people have a natural gift for observation, it can be learned by almost anyone and honed like any other skill. It just takes practice. Counting petals is a good place to start.

Oxalis Oregana

Day 163: I hope my readers will bear with me as my ability to find natural-history subject matter of a visual nature is further curtailed by Washington State Governor Jay Inslee's "stay at home" order which, unsurprisingly, no one in this community seems to be obeying except me. Traffic is flowing past my house in both directions: toward the Park and toward the grocery stores. Meanwhile, I've moved my exercise equipment into the back bedroom and have installed daylight LEDs in both floor lamps in order to have enough light to compensate for the need to have one curtain partially closed to obscure the back neighbour's large 2020 presidential campaign banner. Being denied hikes into the deeper recesses of Nature was bad enough without THAT cropping up in my field of view. Enough, Crow. Take a deep breath, focus your mind and talk about Oxalis. They came here for science, the few who show evidence of having brains.

Although the leaves of Oxalis oregana (aka Redwood Sorrel) resemble those of clover, the plants are not related. Oxalis is a member of its own Family (in the taxonomic sense), the Oxalidaceae (Wood Sorrels). The species occurs only in the western United States and British Columbia. Its three heart-shaped, lightly hairy leaflets are photo-sensitive, drooping downward when light levels are high but returning to a more flattened state when shaded. In certain exposures where shade and sunlight alternate by the minute, the change in position occurs quickly enough to be observable by eye. The flowers may be almost entirely white, or may be striped with pink or purple as they are in the photo. The plants associate with Douglas-fir in Washington as well as with the redwoods which give them their common name. Although the leaves were eaten by native peoples, the plant is not considered edible due to the presence of oxalic acid in the tissues.

Oxalis Oregana, Wood Sorrel

Day 171: Shy little Oxalis oregana (Redwood Sorrel) is common in the Pacific Northwest and often occurs fairly densely where it receives shade from Douglas-fir. Its three-lobed leaves resemble those of clover, although on a grand scale, and they are highly sensitive to light levels. When the sun breaks through the forest canopy, the leaves will fold downward in a matter of minutes, opening again when shade returns. The flowers may be white to pink, and may be marked with darker purple "nectar guides." Pollination is performed largely by syrphid flies. All parts of the plant contain oxalic acid and should not be eaten.