Field Guide
Celebrating a “living fossil” that was only recognized in 1991
Prototype Quillwort is really old, really hard to find and really difficult to identify. That’s why this “living fossil,” was recognized as a species only in 1991
This quillwort species is really old, really hard to find and really difficult to identify. That explains why, despite it being among the most ancient plants, a “living fossil,” the prototype quillwort, or Isoëtes prototypus, was recognized as a species only in 1991.
The genus Isoëtes, known to most as quillwort, is a lycopod from the Isoetaceae family. There are 192 species around the world. The name is derived from the old-english word meaning “root” but historically has meant everything from capers to chamomile (Shakespeare used it to mean “cabbage”). Quillworts are the closest living relatives of those famous “fossil trees,” Lepidodendrons, long-extinct primitive, vascular, tree-like plants that fossilized as intact trunks. The two share some traits, like the fact that their shoot systems evolved into watery roots.
Quillworts in general are an interesting group: most grow submerged in water but look terrestrial. With brittle quill-like leaves that emerge from a small base corm, they can resemble decorative grasses swaying in slowmotion breezes or sodden spiky tropical shrubs. Due to their inaccessibility, they are poorly known and difficult to distinguish from one another. Because their spores are the best means of differentiating them, often you need a microscope to tell two species apart.
The prototype quillwort may be the most mysterious of all, the Greta Garbo of quillworts. This variant, also known as Canadian quillwort and big quillwort, is scarcely seen, not surprisingly since it lives submerged in only 12 unconnected cold spring-fed, nutrient-poor lakes in New Brunswick and Nova Scotia (and one more, south of the border in Maine). The plants are so hard to locate, in fact, that the majority of sites were identified first by discovering plants that had broken away and floated to the surface. Their stiff dark green leaves, in clumps of 10 to 25, are reddish-hued and broad at the base where the reproductive spores develop, gradually tapering to a fine point, a bit like a quill. They grow in dense patches of up to 400 plants per square metre, creating a dense blanket on the pond floor. This means that, despite the small number of sites, there are a surprisingly high number of individual plants, perhaps as many as 250,000. It is hard to say for sure though: they are truly recognizable only by determining the number of chromosomes.
The discoverer was University of Guelph professor D.M. Britton, in 1988. He was an internationally renowned botanist, co-author of the definitive Ferns and Fern Allies of Canada and “the greatest fern authority Canada has known,” according to Canadian Field Naturalist. Don Britton also was, by many accounts, an inspiring teacher, a generous collaborator and a modest soul — not surprising in someone fascinated by ferns, those captivating yet self-effacing plants. A former grad student described Britton’s passion for unravelling “the cytological and morphological mysteries of the exasperatingly difficult aquatic lycophyte genus Isoetes… led us in new and unexpected directions.” Including, presumably, to standing chest-deep in the tannin-stained depths of an unnamed pond in New Brunswick, feet and shins sunk in goopy colloidal sediment.
It was Britton who chose this rather unusual name: prototype. Why “prototype”? Because, there is nothing else like it in the world, he said. He wrote, it “represents a basic diploid entity [but] quite unlike other diploids, it is clear that it is an antecedent in the evolutionary scheme… it is ancestral.” “Diploid” means two full sets of chromosomes per cell. He goes on to say that it “is of great interest to isoetologists” (a job I had never heard of before): as one of only two native diploid quillworts, it is assumed to be the ancestor of several species.
While some of its habitats are protected, the easily uprooted perennial is vulnerable to disturbances from swimmers, paddlers, fishing, anchors and water intake pipes. Since many of the lakes where it can be found have numerous cottages and increasing shoreline deforestation, the threats are manifold. It is listed as a species of concern by the federal government, as endangered by New Brunswick and as vulnerable and in need of protection by Nova Scotia. What a strange plant this is. Fragile and vulnerable and yet it dates back millennia. Found in only a few locations and yet plentiful therein. Prototype quillwort is truly a paradox.