by Fred Schueler & Aleta Karstad, Fragile Inheritance Natural History
On the radio and internet, you often encounter pitches for stories or movies of unknown aliens living among us, but these are imaginary or fictional. It was quite unexpected to hear, in 1987, real news that the widespread and familiar Narrow-leaved Cattail, Typha angustifolia, had been shown to be a European species, with a documented spread across North America from a first record in 1820. The first Ontario record was in 1880, and since then it has spread (which we’ve helped to document from the 1070s onward) across the Canadian Prairies.
The bombshell hypothesis that only the Broad-leaved Cattail, Typha latifolia, was native to northern North America was dropped by Ronald L. Stuckey & Douglas P. Salamon in an abstract in the Ohio Journal of Science, and has since been confirmed by fossil pollen records and genetic studies. One of these studies even suggests (on the basis of genetic similarity, and I don’t know how plausibly) that in Europe their Broad-leaved species was an introduction from North America.
Since Cattails make up a major portion of wetland and roadside vegetation, and the two species have been well known to partition these habitats between themselves and their abundant hybrid, Typha x glauca, the idea that the Narrow-leaves were aliens was a pretty considerable reinterpretation of the landscape.
Cattails are among the plants that reproduce by seed only infrequently, but, once established, spread vegetatively by subsurface stems or rhizomes. This means that the genetically identical descendants of an original seedling or clone often come to dominate a patch of marsh or a few metres of a roadside ditch.
In Eastern Ontario, you can easily pick out these clones because they differ conspicuously from their neighbours. This is because many, perhaps most, of them are hybrids. Along with the width of the leaves (the basis of the English and scientific names) the species are distinguished by the length of the gap between male and female flowers on the Cattail spike. The female flowers make up the familiar brown club of the seed head, but before they thicken and turn brown, the pencil-thin green male spike fluffs out in yellow pollen for a few days. There’s a gap, exposing the smooth round stem, of a few to several centimetres between the male and female flowers of the Narrow-leaves, while in Broad-leaves there is no gap. Those are the parent species. The hybrids’ gap varies between one and two centimetres.
Narrow-leaves thrive in drier sites than Broad-leaves, but require more nutrients and like damp mineral soil rather than organic muck. The hybrid is taller than either parent, and forms floating mats in the deepest water of marshes, especially where the water level frequently fluctuates. This means that many of our largest cattail marshes, especially around the Great Lakes, are almost entirely hybrids. In the Boreal Forest, Narrow-leaves, likely carried as seeds on construction equipment, exploited the mineral soil exposed in roadside ditches during paving and road-building in the 1960’s and 1970’s, but north of North Bay the colonies have seemed to gradually fade away as organic soil accumulated in the ditches. For us, the emblem of the triumph of this European invader came on 16 October 2014, at Pipestone Creek, near Broadview, in southeastern Saskatchewan, where we saw an entire valley marsh tan with Narrow-leaves, and none of the greyish patches which we’d have recognized as native Broad-leaves. Coming back from that trip, Fred submitted a manuscript which suggested that under the standard federal criteria, the native Broad-leaved Cattail now qualifies as a species-at-risk on the southern prairies.
Locally, in our database, within 20 km of the Oxford Mills dam, we find 95 mentions of Narrow-leaved Cattail, 77 of Broad-leaves, and 107 of hybrids, so only 28% of the mentions are natives, which falls in the formal 30% criterion for endangered status. Within a wetland, the Broad-leaves are often in the more interior areas away from roads and disturbance.
In the muskeg-like Long Swamp Fen, 7 km S of North Augusta (which is moving towards becoming a Provincial Park because of the rare species of plants that live there) we’re monitoring the spread of Narrow-leaved Cattails out from North Augusta Road into the fen. This invasion may eventually threaten the rare plants for which the site was protected.
Cattails are one of those plants of which it is said “Any parts which aren’t too tough to chew are edible.” However, Cattails are also known to accumulate various environmental toxins, so shouldn’t be foraged from roadsides or potentially contaminated sites. The starchy root-like rhizomes can be cooked after removing the skin, the bases of the young leaves, plucked from the centre of the plants, can be used in a spring salad, and later in the spring cooked as “Cossack Asparagus.” The firm, unopened male flower spikes can be cooked as a sweet-corn-like vegetable (though not sweet at all) or later the pollen can be shaken into a container, and used as a golden flour in baking. The rhizomes can also be pounded to separate the flakes of starch from the fibres, and the starch then used in baking. Snapping off the male flowerheads from the hybrids, to freeze for the winter, is one of our major foraging activities – traditionally around Canada Day, but recently, with global warming, in mid-to-late June.
Like so many kinds of organisms, Cattails weave a complex pattern of nativity, invasion, hybridization, and utility over our young post-glacial landscape, and the major clue to tracing this pattern is the length of the gap between the female and male flowerheads.