Eriophorum angustifolium / narrow-leaved cottongrass

Adjectives: clonal, emergent aquatic, exposed, fen, highly visible, native, striking, wet meadows

Also known as: common cottonsedge, bog cotton, tall cottongrass, common cottongrass

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Should you decide to put on your wellies and venture into the fens in the Teton River flood plain, you will (hopefully) be greeted by the white, puffy infructescences of the narrow-leaved cottongrass. Overall, it is a rather dull looking plant in the winter (it is perennial) or spring, but after flowering, it is quite striking because of the white fruits, like balls of cotton (to which it is absolutely not related).

Indeed, this cottongrass is found not only in fens, but around the northern parts of the world in peat, fens, bogs and wetlands.

Cottongrass begins to flower in May. The flowers are unremarkable, dull yellow things, not unusual for wind pollinated sedges. The real beauty begins after fertilization in early June, when the distinctive, white tufts of cotton develop. Actually, these are infructescences composed of long white pappi (bristles) attached to small seeds… sort of dandelion-like, but again, totally unrelated. This is the form you would normally be drawn to, and it is what is shown in the gallery photos. Happily, this stage hangs around for a good bit of the summer before the seeds are wind dispersed.

The fact that multiple flower heads are associated with each stem is a distinguishing characteristic (compared to other species in the genus), several of which actually occur in Idaho.

There is, of course, more to the plants than the beautiful seed heads. Like other sedges, the stem of cottongrass is triangular, smooth and green. The leaves are stiff, pointy and otherwise what one would call “grass-like”. Leaf-like bracts extend above the  inflorescence; these are also are triangular, pointed and dark. Basically, however, there are not many leaves on the plants, but they do technically occur both at the base and along the stems.

Narrow-leaved cottongrass reproduces by seed, but it is also a clonal perennial. It has creeping rhizomes with lots of unbranched, pink, translucent roots. One day, I will dig some up just to see.

Interesting bits – Despite the name and the look, the fibers of cottongrasses in general are not suited for textile making because they are too short and brittle. They have, however, been used in the production of paper alternatives, as pillow stuffing, as candle-wicks and fire starters, and, during World War I, as wound-dressings.

E. angustifolium can grow with enough density to hide a bog or fen. If you see a really dense stand, take care… you may be entering a place where it is not really safe to walk (without getting really wet).

In some places, geese feed on the plants, uprooting them. This bears looking at more closely in the Valley, just for the heck of it.

And finally, even when E. angustifolium is growing in standing water, it has been reported the it tightly controls water loss through transpiration and that the stems present a high resistance to water flow. Physiologically, this is interesting and a bit hard to explain.