few-seeded sedge

(Carex oligosperma)

               
Conservation Status

IUCN Red List

not yet assessed

few-seeded sedge

NatureServe

N3N4 - Vulnerable to Apparently Secure

SNR - Unranked

Minnesota

not listed

Wetland
Indicator
Status

Great Plains

OBL - Obligate wetland

Midwest

OBL - Obligate wetland

Northcentral & Northeast

OBL - Obligate wetland

Nativity

Native

Occurrence

Common in sphagnum bogs

Habitat

Wet. Bogs, fens, swamps, marshes, lakeshores, river banks.

Photo by Peter M. Dzuik
Flowering

May to June

     
Height

14 to 40

     

Identification

This is a 14 to 40 tall, erect, perennial sedge that rises on a single stalk or in a loose clump with just a few stalks from a long, creeping, underground stalk (rhizome). It often forms loose colonies.

The stem (culm) is slender, broadly three-angled in cross section, smooth, and tinged purple at the base. It is hairless but is sometimes rough to the touch on the angles near the tip.

The leaves are wiry, stiff, dark green, hairless, and 1 32 to wide. The margins are rolled inwards. The lower part of the leaf that surrounds the stem (sheath) of basal leaves is reddish-purple and usually persists into the next season. The appendage a the junction of the leaf sheath (ligule) is as wide or wider than long.

The flowers appear from May to June. The inflorescence consists of 2 to 4 flower clusters (spikes) at the end of the culm. It is 1¼ to 8 long and is subtended by a single modified leaf (bract). The bract is stiff, straight, wiry, and usually 1¼ to 6 long, sometimes up to 10 long. It is slightly shorter than or slightly exceeds the tip of the staminate spike. The spikes are unisexual, with all female (pistillate) or male (staminate) flowers. There are 1 to 3 lateral pistillate spikes and usually just a single terminal staminate spike. The lowest spike rises erect from the axil of the inflorescence bract. If there are one or two more pistillate spikes they are widely separated from the first and from each other. The staminate spike is held well above the uppermost pistillate spike.

The pistillate spikes are erect and stalkless or nearly stalkless. They are short, plump, and egg-shaped to short-cylindric. They consist of just 3 to 15 inflated, to ¼ long spikelets. The spikelet is a single flower subtended by a sac-like structure (perigynium) which is in turn subtended by a modified bract (scale). The scale is egg-shaped, to ¼ long, and wide, shorter than the perigynium. It is sharply pointed but does not have a bristle-like extension (awn) at the tip.

The perigynium is ascending, leathery, and shiny. It is inflated, egg shaped, to ¼ long, and tapered at the tip. It ends in a 1 64 to 1 32 long, prolonged, terminal appendage (beak). There are 7 to 15 distinct, longitudinal veins that extend onto the beak. Enclosed by the perigynium is a single ovary with one style. The style is branched into three stigmas that project from the narrow opening at the top of the perigynium.

Staminate spikes are slender, club-like, linear in outline, ascending to erect, and stalkless or short-stalked. They consist of many flowers in a dense, spiral arrangement. Staminate flowers have three stamens.

The fruit is a dry, brown, one-seeded capsule (achene) with the three dried stigmas still attached. It is three-angled and 1 16 to long, almost as large as the perigynium. It matures from June to July and persists on the plant into August or September.

 
Similar
Species

Woolly-fruit sedge (Carex lasiocarpa) inside of leaf sheaths have distinctly raised cross lines (septations) between the veins.


Distribution Distribution Map   Sources: 2, 3, 4, 5, 24, 28.

Comments

 


Taxonomy

Family:

Cyperaceae (sedge)

 

Subfamily:

Cyperoideae

 

Tribe:

Cariceae

 
Synonyms

Carex oligosperma var. churchilliana

Carex oligosperma var. oligosperma

 
Common
Names

bog wiregrass sedge

few-fruited sedge

few-seeded hop sedge

few-seeded sedge

fewseed sedge

wiregrass


 

 

 

 

 

Glossary

achene

A dry, one-chambered, single-seeded seed capsule, formed from a single carpel, with the seed attached to the membranous outer layer (wall) only by the seed stalk; the wall, formed entirely from the wall of the superior ovary, does not split open at maturity, but relies on decay or predation to release the contents.

 

axil

The upper angle where a branch, stem, leaf stalk, or vein diverges.

 

beak

A comparatively short and stout, narrow or prolonged tip on a thickened organ, as on some fruits and seeds.

 

bract

Modified leaf at the base of a flower stalk or flower cluster.

 

culm

The hollow or pithy stem of a grass, sedge, or rush.

 

ligule

In grasses and sedges, a membranous appendage at the junction of the leaf and the leaf sheath, sometimes no more than a fringe of hairs. In flowering plants, the flat, strap-shaped, petal-like portion of the corolla of a ray floret.

 

linear

Long, straight, and narrow, with more or less parallel sides, like a blade of grass

 

perigynium

In Carex and other closely related sedges, a sac-like structure that surrounds the pistillate flower and later encloses the achene. Plural: perigynia.

 

pistillate

Referring to a flower that has a female reproductive organ (pistil) but does not have male reproductive organs (stamens).

 

rhizome

A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.

 

scale

In plants, a small, usually flat and thin, modified leaf resembling the scale of a fish.

 

sheath

The lower part of the leaf that surrounds the stem.

 

spike

The arrangement of an unbranched, elongated inflorescence with stalkless flowers that mature from the base toward the tip. In Cyperaceae, it also denotes a collection of one or more stalkless flowers, each subtended by scales, on a single inflorescence axis.

 

spikelet

In flowering plants, a small spike. In grasses and sedges, the basic unit of inflorescence. In grasses, composed of usually two glumes and one or more florets. In sedges, a single flower and its single associated scale

 

staminate

Referring to a flower that has a male reproductive organs (stamens) but does not have a female reproductive organ (pistil).

 

       

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Katy Chayka


  few-seeded sedge   few-seeded sedge

       
       

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  Carex oligosperma
Timothy M. Jones
 
   
 
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Uploaded on Aug 26, 2007

Carex oligosperma habit and dissection

 
     

 

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Katy Chayka
9/6/2015

Location: Blaine Preserve SNA

few-seeded sedge


     
     
 

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