Carex annectens (Yellow-fruit Sedge)
|Also known as:||Yellow Fox Sedge|
|Habitat:||sun; moist to dry; sedge meadows, prairie swales, marsh edges, stream banks, pond margins, sand dunes|
|Fruiting season:||June - August|
|Plant height:||18 to 40 inches|
|Wetland Indicator Status:||GP: FACW MW: FACW NCNE: FACW|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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A cluster 1½ to 3¾ inches long at the top of the stem, compound with 10 to 15 branches, the lower branches with a few stalkless spikes each, and the upper branches more obscure often with a single spike each. Branches are overlapping, the upper crowded together and the lower branches may be slightly separated from each other. All spikes are alike with staminate (male) flowers at the tip and pistillate (female) flowers at the base (androgynous). At the base of each spike is a bristle-like bract; the lowest bract is longest, usually longer than the associated branch but does not usually over-top the terminal spike. Bracts become shorter as they ascend the stem and are obscure in the uppermost spikes.
Leaves and stems:
Leaves are basal and alternate, mostly on the lower half of the stem, 2 to 5 mm wide, the longest up to 2 feet long, the upper leaves usually not over-topping the flowering stems. Stem leaf sheaths are straight across to convex at the tip, cross-wrinkled (rugulose) on the front, snugly wrap the stem, translucent whitish, fragile and easily torn, and may be spotted red or brown. The ligule (membrane where the leaf joins the sheath) is wider than long. Leaves are hairless and V-shaped in cross-section when young.
Bases are wrapped in a brown sheath that may become fibrous with age. Stems are erect to ascending, 3-sided, slender, firm, rough textured below the spike clusters, mostly over-topping the leaves and elongating up to about 3 feet at maturity. Plants are clump-forming and not colony-forming.
Fruit develops starting in mid-June, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Pistillate spikes each contain several to many fruits that are ascending to spreading and tightly crowded on the stalk.
Pistillate scales are lance-shaped, translucent whitish to brown with a green midrib that extends to an awn up to 1.5 mm long, the body much shorter than the perigynia but the awn may surpass it. Perigynia are 1.9 to 3 mm long, 1.2 to 2.2 mm wide, golden to orange-brown at maturity, faintly 3-veined, hairless, not much inflated but slightly spongy at the base, flattened on the back side, the body nearly round in outline, widest near the middle of the body, the base rounded to somewhat tapered, the tip abruptly tapering to a toothed beak not more than half as long as the body and is finely toothed along the edges. Achenes are 1.2 to 1.5 mm long and 1 mm wide, flattened lens-shaped, egg-shaped, glossy, and mature to dark golden brown.
Carex annectens is an uncommon sedge of open, moist to dry habitats including meadows, prairie swales, margins of marshes and ponds, and sand dunes. According to the DNR, historically it is known primarily as a prairie species, but by the time it was first discovered in Minnesota in 1978, most of the native prairie had been converted to agriculture or otherwise developed so its original distribution in the state is unknown. Several scattered populations have since been located but it is still considered rare. It was listed as a Special Concern species in 1984.
Carex is a large genus, with over 600 species in North America and 150+ in Minnesota alone. They are grouped into sections, the species in each group having common traits. Carex annectens is in the Multiflorae section; some of its common traits are: clump forming, sometimes long-rhizomatous, stems usually very slender just below the spike clusters, basal sheaths usually fibrous, sheath fronts cross-wrinkled (rugose) and often red-dotted, leaves hairless and V-shaped in cross-section when young, spike clusters branched (compound) or not (simple) and often crowded, 8 to 20+ stalkless spikes (usually 15+), terminal spike with staminate flowers at the tip (androgynous), lateral spikes androgynous or all pistillate, pistillate scales awned or not, perigynia veined on the front, veined or not on the back, widest at/near the middle, the base rounded with spongy tissue, tapered at the tip to a toothed beak, not more than twice as long as wide, flattened lens-shaped achenes. Several of these traits are shared with the Phaestoglochin and Vulpinae sections; the former usually has fewer than 15 spikes and clusters are usually unbranched, the latter usually has stout, spongy stems, perigynia widest at or near the base, mostly at least twice as long as wide, and often more distinct, spongy tissue at the perigynia base.
Carex annectens is distinguished by its firm, slender, 3-sided stems that are rise well above the leaves; leaf sheaths that are cross-wrinkled on the front; cluster usually branched at least at the base, branches usually tightly crowded except at the base; androgynous spikes; perigynia 1.9 to 3 mm long with a nearly round body, abruptly tapering to a toothed beak that is much shorter than the body, golden to orange-brown at maturity; awned pistillate scales with the awn up to 1.5 mm long and may extend past the perigynia tip. Of note is many references describe red or brown spotting on the sheaths, but we did not observe this on our specimens, even at high magnification. The only other member of the Multiflorae section in Minnesota is Carex vulpinoidea, which prefers wetter habitats, has leaves longer than the stems, usually longer and less congested spikes, and the perigynia beak tapers more gradually and is about as long as the body.
Carex annectens is known by synonym C. brachyglossa in some references. Others note multiple vars, with our native var. xanthocarpa, but these vars are not recognized in Minnesota.
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- Carex annectens plant
- Carex annectens plant
- Carex annectens plants
- Carex annectens on a pond margin
- fruiting stem rises above the leaves
- mature spikes
- maturing spikes
Photos by K. Chayka and Peter M. Dziuk taken in Washington County.
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