You may be wondering why I shared two very similar photographs today. There is a significant difference between them, though it isn’t immediately evident. The photographs were taken 7 years apart.
If clicking on the images to get the pop-up gallery mode, you should be able to toggle back-and-forth to compare the images with the left and right arrow keys. I’ve looked at them closely , and I can see only a small amount of growth on a few of the lichens encrusting the rocks, though most show no noticeable increase within the scale of these images. Nothing like photographic evidence to prove that lichens in high-elevations grow slowly–a reminder to myself to tread lightly.
The leafy Oxyria digyna arugably shows some growth, but it’s a bit difficult to tell with the shift in perspective from re-taking the photo one step to the right or so (I was trying to recreate the old photo from memory…). However, one wouldn’t expect significant growth from an arctic-alpine vascular plant either, given the short growing season, generally cooler temperatures, and relative lack of nitrogen. Mountain sorrel is an important traditional food plant for peoples across the northern hemisphere’s arctic, boreal, and high alpine regions. Positive attributes include provision of vitamin C, ubiquity and abundance (i.e., one can depend on encountering it, if exploring), and taste, which can vary from sweet to sour depending on the concentration of anthocyanin pigments. According to the link above, the higher the concentration of anthocyanins (i.e., the redder the colour of the leaves), the more sour the taste.
The Flora of North America account for Oxyria digyna has additional details about the morphology, habitat, and distribution of this species. New England Wild Flower Society’s GoBotany site has additional photographs: Oxyria digyna.