European bur-reed

(Sparganium emersum)

               
Conservation Status

IUCN Red List

LC - Least Concern

European bur-reed

NatureServe

NNR - Unranked

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

Habitat

Shallow water. Margins of lakes and swamps, in ponds and streams, and in backwaters of large rivers. Full sun. Muddy soil.

Flowering

June to August

 
Flower Color

White or whitish

 
Height

8 to 24

 

Identification

This is an 8 to 24 tall, erect, perennial, emergent or floating, aquatic forb that rises on basal leaves and a single stem from fibrous roots and an underground horizontal stem (rhizome).

Basal leaves are strap-shaped (linear). Some may stand above the water (emergent), while others float on the surface. They surround (sheath) the stem at the base and taper to a point at the tip. Emergent leaves are stiff, spongy, 12 to 32 long, and to wide. They are parallel-veined and flat (not rounded on the back), and partially to entirely folded with a raised ridge (keeled). The upper and lower surfaces are hairless. The margins are untoothed. Floating leaves are similar but limp, up to 80 long, to 11 16wide, and keeled, at least near the base.

Stem leaves are reduced to persistent, leaf-like bracts. The bracts are alternate, ascending or spreading, broadened and thickened at the base, and otherwise similar to the basal leaves. They become much smaller as they ascend the stem.

The stem is hairless, unbranched, and usually erect, sometimes floating. Stem leaves are

Male and female inflorescences are produced on the same plant. Flowers are grouped in dense, spherical, unisexual heads with numerous flowers on an erect, unbranched, somewhat zigzagged, 4 to 8 long stalk at the end of the stem. There are usually 3 to 7, sometimes up to 10, male (staminate) heads at the top and 1 to 6 female (pistillate) heads below. The lowermost pistillate heads are on stalks that connect to the stem above, not in, the uppermost bract axils. The upper pistillate heads and the staminate heads are stalkless. Pistillate heads are to 1 in diameter when in fruit.

Individual flowers are tiny. Staminate flowers have 1 to 6 tepals and 2 to 8 stamens. The tepals are free, not united at the base. They are scale-like, club-shaped to spatula-shaped, and green at first, soon turning white or whitish. They do not have a dark thickened area just below the tip. The margin at the tip is irregularly toothed, appearing gnawed. The stamens have filaments that are much longer than the tepals. The anthers are attached by the base to the filaments. Pistillate flowers have 1 style with 1 stigma. The style is much longer than the tepals. The stigma is white to greenish. The flowers are pollinated by wind.

The fruit is similar to and often called an achene but is actually a drupe, with a fleshy exterior surrounding a single stone-like seed. It is shiny, 3 16long, 1 16 wide, and spindle-shaped, widest at the middle and tapered at both ends. It is green at first, turning reddish-brown at maturity. The dried style persists as a beak attached to the tip. The beak is shorter than the body.

 
Similar
Species

American bur-reed (Sparganium americanum) inflorescence is sometimes branched. The pistillate heads are stalkless in the bract axils. The fruits are not shiny.

Common bur-reed (Sparganium eurycarpum) is a larger plant, up to 40 tall. All or most of the pistillate flowers have two stigmas. The fruit is broadly pyramid-shaped.

Narrow-leaved cattail (Typha angustifolia) leaves are conspicuously rounded on the back.


Distribution Distribution Map  

Sources: 2, 4, 5, 7, 28, 29.


Comments

Taxonomy
The genus Sparganium was formerly placed in the family Sparganiaceae. It was moved to the cat-tail (Typhaceae) family in 2009 based on evolutionary (phylogenetic) analysis.


Taxonomy

Family:

Typhaceae (cat-tail)

 

Tribe:

Sparganieae

 
Synonyms

Sparganium acaule

Sparganium chlorocarpum

Sparganium chlorocarpum var. acaule

Sparganium simplex

 
Common
Names

European bur-reed

greenfruit bur-reed

narrowleaf bur-reed

narrow-leaved burreed

unbranched bur-reed

   

 

 

 

 

 

 

 

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.

 

bract

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

 

drupe

A fleshy fruit with usually a single hard, stone-like core, like a cherry or peach; a stone fruit.

 

emergent

Growing out of the water and held above the water surface.

 

filament

On plants: The thread-like stalk of a stamen which supports the anther. On Lepidoptera: One of a pair of long, thin, fleshy extensions extending from the thorax, and sometimes also from the abdomen, of a caterpillar.

 

keeled

Folded, as in a grass blade, or with a raised ridge, as in a grass sheath; like the keel of a boat.

 

linear

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

 

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.

 

staminate

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

 

stigma

In plants, the portion of the female part of the flower that is receptive to pollen. In Lepidoptera, an area of specialized scent scales on the forewing of some skippers, hairstreaks, and moths. In Odonata, a thickened, dark or opaque cell near the tip of the wing on the leading edge.

 

tepal

Refers to both the petals and the sepals of a flower when they are similar in appearance and difficult to tell apart. Tepals are common in lilies and tulips.

       

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  European bur-reed    
       

Male Inflorescence

  European bur-reed   European bur-reed
       

Female Inflorescence

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  European Bur-Reed (Sparganium Emersum) - 2012-07-01
Westdelta
 
   
 
About

Published on Jul 2, 2012

Sparganium emersum is a species of flowering plant in the cat-tail family known by the common name European bur-reed.

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De kleine egelskop (Sparganium emersum) is een vaste plant uit de egelskopfamilie (Sparganiaceae).

52.02455 4.30568

 
     

 

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