With some 1,850 native plant species in Ohio, there are plenty of mysteries. Many plants are poorly known, even some of the common ones; get into the realm of the rare and sometimes hardly anyone seems to know anything. The species that follows ranks high in the botanical mystery world.
While researching gnatcatcher and hummingbird nests at the Ohio State University's Museum of Biological Diversity today, I had occasion to pull this sheet from the herbarium. It is perhaps the last specimen collected in Ohio of an enigmatic plant called Waterplantain Spearwort, Ranunculus ambigens. Dave Spooner took it nearly 29 years ago, in Scioto County. There are a number of other Ohio records, but most are far older than this one.
It's much easier to pick up on NEW occurrences: plants or animals that are appearing where they haven't previously. When species gradually slip away over time, especially ones that don't loom large on people's radar screens, detecting their disappearance is harder. Had we not been immersed in looking intimately at every Ohio species of plant for our project, we certainly wouldn't have noticed the riddle of the missing spearwort.
My original theory about this loss involved two factors: habitat, and time of year. Waterplantain Spearwort grows in marshes that are densely vegetated, and might hold a foot or two of water at most seasons. Such haunts are often shunned due to the difficulty of getting around. Two, this plant blooms in the midst of summer, when heat, humidity and bugs are at their worst, further discouraging exploration.
But, especially in the last decade, botanists have done rather heavy exploration of such habitats in summer, and no one has turned up the spearwort. One might attribute its loss to the overall loss of wetlands - Ohio has lost about 90% of its presettlement wetlands - but that's too simplistic an explanation, in my view. There are still plenty of apparently suitable sites, including some of the places that this species was once found in.
My hunch is that a water quality issue is at work here. Increased turbidity - muddying of the waters - or perhaps chemical contaminants such as fertilizers may be impacting the spearwort. It grows,and presumably germinates, in water, and those factors may be inhibiting its ability to grow.
From what I know of Ranunculus ambigens, it is a worthy candidate for Federal listing, and should be the subject of a thorough study to determine its overall status. If anyone knows anything about the plant, I'd love to learn more.