Carex projecta (Necklace Sedge)

Plant Info
Also known as:
Genus:Carex
Family:Cyperaceae (Sedge)
Life cycle:perennial
Origin:native
Habitat:part shade, shade; moist to wet; forests, thickets, meadows, swamps, swales, shores, river and creek banks
Fruiting season:July - August
Plant height:12 to 36 inches
Wetland Indicator Status:GP: FACW MW: FACW NCNE: FACW
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Spikes: Flower shape: indistinct Cluster type: spike

[photo of spike clusters] 8 to 15 spikes each 9 to 12 mm (to ~½ inch) long, all at the tip of the stem, mostly overlapping, the upper spikes often tightly crowded, the lower more separated, the inflorescence (group of spikes) up to about 2½ inches long and typically nodding or bent. All spikes are stalkless, erect to ascending, rounded at the tip, mostly tapered at the base and club-shaped in outline, with staminate (male) flowers at the base and pistillate (female) flowers at the tip (gynecandrous). At the base of the lowest spike is a scale-like bract with a bristle-like tip that may be longer than the spike but does not overtop the terminal spike.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of sheath and ligule] Leaves are alternate with 4 to 6 leaves on the lower half of the stem, up to 16 inches long, 3 to 7 mm wide, flat, hairless, rough along the edges especially near the tip, and shorter than the flowering stems. Stem leaf sheaths are mostly green nearly to the tip, the whitish translucent tip extends above the leaf base and is U- to V-shaped across the top edge. Sheaths loosely wrap the stem especially at the tip, the leaf midvein and edges becoming continuous wings or ridges down the sides and back of the sheath. The ligule (membrane where the leaf joins the sheath) is longer than wide.

[photo of plant base] Bases are wrapped in a brown sheath that may be somewhat fibrous, with old leaves often persisting to the next season. Stems are hairless, mostly erect, 3-sided in cross-section, mostly smooth except just below the spikes. Stems may elongate to 36 inches at maturity and are longer than most leaves. Plants are clump forming from a mix of flowering and vegetative shoots. Late in the season, old prostrate stems may form buds at the nodes that take root, forming new plants the following year.

Fruit: Fruit type: seed_without_plume

[close-up of mature spike] Fruit develops in early to mid summer, the spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Perigynia are ascending to loosely spreading. Each spike contains 15 to 30 fruits.

[photo of perigynia scale and achene] Pistillate scales are lance-oblong, translucent whitish to brown-tinged with a green or brown midrib that does not extend to the tip, blunt to pointed at the tip, half to about ¾ as long as the perigynia. Perigynia are 2.9 to 4.3 mm long, 1.2 to 1.6 mm wide, straw-colored to light reddish-brown at maturity, hairless, 5 to 8-veined on the front, 3 to 6-veined on the back (may be faint), flattened, not inflated, the body lance-elliptic, tapering at the base, tapered to a beak .9 to 1.5 mm long, and has a translucent, whitish, papery wing .1 to .2 mm wide around the edges that abruptly narrows at about the middle of the perigynia body. Achenes are lens-shaped, brown at maturity, 1.1 to 1.7 mm long, .6 to 1 mm wide, oblong-elliptic, distinctly longer than wide; the distance from the tip of the achene to the tip of the beak is 1.6 to 2.4 mm.

Notes:

Carex projecta is a common sedge of moist to wet places in the eastern 2/3 of the state, mostly north of the Twin Cities. It is found in floodplain forest, swales, swamps, wet meadows, ditches, and the margins of rivers, lakes and ponds. It tolerates full sun but is more often found in shadier sites.

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 projecta is a member of the Ovales section, a notoriously difficult group. Some common traits are: usually clump forming, basal sheaths brown and somewhat fibrous, leaves V-shaped when young; 2 to 20 stalkless spikes all at the stem tip and crowded or not, spikes usually all pistillate at the tip and staminate at the base (gynecandrous), lowest bracts scale-like usually with a bristle tip, pistillate scales blunt to pointed at the tip and sometimes awned; perigynia erect to spreading, hairless, veinless to conspicuously veined on one or both surfaces, flat, beaked, usually with a translucent, papery wing; achenes lens-shaped.

Some traits to look at in Ovales are whether spikes are all crowded at the tip or more loosely arranged, whether the inflorescence is nodding or mostly erect, the shape of the spike (round vs. elliptic vs. club-shaped), the size and shape of the perigynia particularly the body (e.g. round vs. elliptic), the width of the wing and whether it extends all the way to the base, whether there are distinct veins on one or both sides of the perigynia, the length of the pistillate scale relative to the perigynia, the shape of the achene, leaf width, and whether sheaths are papillose, but strong magnification (30x or more) is required to see this. Habitat can also be a factor, and a metric scale is essential since fractions of millimeters make a difference.

Carex projecta is distinguished from other Minnesota Ovales species by widest leaves 4 to 7 mm wide, loose sheaths that are winged or ridged down the sides and back (continuous with the leaf midvein and edges); 8 to 15 spikes in a nodding or bent inflorescence, the lower spikes typically more separated than the upper, spikes rounded at the tip and mostly tapered at the base, lowest perigynia on a spike ascending to somewhat spreading; pistillate scales shorter than the perigynia and the midvein not reaching the tip; perigynia 2.9 to 4.3 mm long, the body lance-elliptic, veined on both sides (sometimes faintly), the wing .1 to .2 mm wide, widest above the achene and not reaching to the base. The distance from the tip of the achene to the tip of the beak is 1.6 to 2.4 mm. It is usually found in moist to wet soil, often in shade.

The loose, winged sheaths and prostrate stems rooting at the nodes are traits shared with Carex cristatella and Carex tribuloides and when fruiting stems are not present they can be very difficult to distinguish. The spikes of both are usually more congested at the stem tip in a typically straight, erect inflorescence, sometimes slightly nodding. C. cristatella spikes are also more globular, consistently rounded at the base, and the lowest perigynia in a spike are widely spreading to reflexed. C. tribuloides usually has more perigynia per spike, 40 or more.

The nodding inflorescence is similar to several other members of Ovales, in particular C. tenera, C. echinodesC. foenea and C. scoparia, which may have fewer than 8 spikes, widest leaves less than 4 mm, and/or tight sheaths.

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More photos

Photos by K. Chayka and Peter M. Dziuk taken in Lake and Pine counties.

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