spikes:

1 to 17 stalked spikes arising from leaf axils on the upper stem, each spike with 3 to 10 spikelets alternately arranged on the central stalk (rachis). Spikes are erect to ascending with spikelets ascending to spreading.

Spikelets are 1.5 to 3 cm long (½ to 1 inch), very slender, somewhat flattened, with 4 to 8 perfect flowers (both male and female parts), each subtended by a scale. Scales are 5 to 9.5 mm long, 1.4 to 2.5 mm wide, lance-oblong, pointed at the tip, tightly appressed and overlapping, green with brown papery edging, and 5 to 9 nerves that are slightly rough.

Leaves and stems:

Leaves are all alternate, spiraling the stem with 3 leaves in a cycle (3-ranked), appearing as 3 columns when viewed from the top. Leaves are hairless, flat, leathery, up to 6 inches long and 8 mm (1/3 inch) wide, becoming smaller on the upper stem and the lowest reduced to bladeless sheaths.

Sheaths are closed, surrounding the stem, convex to dome-shaped at the tip, papery with brown edging. The ligule (membrane where the leaf joins the sheath) has a band of loose, papery tissue along the edge. Stems are multiple from the base, erect, unbranched, round in cross-section, jointed, hairless, green, and usually leafy. Loose colonies are often formed from spreading rhizomes.

Fruit:

A flower produces a single seed (achene), the body 2 to 4 mm long, narrowly elliptic, flattened lens-shaped, the persistent style forming a slender beak about as long as the body. Surrounding the base are 5 to 9 slender, barbed bristles more or less equal in length and about as long as the achene including the beak.

Notes:

Three-way Sedge is a common sedge of open, wet places including lake and pond shores, marshes and swamps, often growing in shallow water. More similar to Cyperus than Carex sedges, it is easy to identify from its unique 3-ranked leaves combined with round stems and spikes arising from the leaf axils. There are 2 recognized varieties of D. arundinacium: var. boreale is a smaller plant with a limited range in Canada, var. arundinaceum is described above and widespread in North America, especially east of the Mississippi River, and including Minnesota.