North American common reed

(Phragmites australis ssp. americanus)

               
Conservation Status

IUCN Red List

LC - Least Concern

North American common reed

NatureServe

N4 - Apparently Secure

SNR - Unranked

Minnesota

not listed

Wetland
Indicator
Status

Great Plains

FACW - Facultative wetland

Midwest

FACW - Facultative wetland

Northcentral & Northeast

FACW - Facultative wetland

Nativity

Native

Occurrence

Common and widespread in Minnesota

Habitat

Wet and muddy areas. Marshes, sloughs, lake shores, and alongside streams.

Flowering

July to August

Height

4 to 16


Identification

This is a perennial, reed-like grass that rises on a single stem from an underground stem (rhizome) and fibrous roots. It slowly forms large colonies that are not dense enough to crowd out all other species. The rhizome is stout, almost perfectly round in cross section, and usually under in diameter.

The stem (culm) is annual, stout, hollow between the nodes, and unbranched. It is 3 16 to in diameter and usually 4 to 6½ in height, but may be 8½ tall or taller. It is flexible, leafy, and hairless, shiny, smooth, and light green to maroon, sometimes maroon only at the nodes. It is sometimes covered with a whitish, waxy film (glaucous). There are often small black spots between the nodes caused by a native fungus. In the spring and summer the lower part of the culm, when the leaf is removed, is reddish to chestnut brown. In the winter it is light chestnut brown to light brownish-gray.

The leaves are alternate, ascending to arching, yellowish-green, and deciduous, falling away in the winter and exposing the culm. The blades are linear lance-shaped, flat, flexible, 6 to 24 long, and ¾ to 1½ wide. They taper to a slender, thread-like point at the tip. The upper and lower surfaces are hairless. The upper surface has numerous parallel veins. The midvein is noticeably thickened on the underside. The lower part of the leaf that surrounds the stem (sheath) is usually hairless, sometimes hairy along the margins. The margins of the sheath overlap. Where the leaf blade meets the sheath there is a thin, pliable appendage (ligule). The ligule is 1.0 to 1.7 mm long and has a fringe of white hairs. In the winter any sheaths remaining on the culm pull away easily.

The inflorescence is a large, dense, plume-like cluster (panicle) of numerous ascending to drooping branches. The panicle is egg-shaped to lance-shaped in outline, 6 to 14 long, and 3 to 8 wide. It is silky and purplish or reddish when in bloom, light tan to dark brown when in fruit.

Each spikelet is egg-shaped to inversely triangular on outline, somewhat flattened, and to long. One spikelet consists of an upper and lower protective bract (glume) and 3 to 8 florets. The lower 1 or 2 florets are male (staminate), the upper 1 or 2 are reduced in size and nonfunctional (sterile), and the remaining ones contain both male and female parts (bisexual). The florets are closely spaced along a zigzagged central axis (rachilla). The rachilla is densely covered with silky, ¼ to long hairs. The glumes have 1 to 3 veins, are hairless, and are shorter than the florets. The lower glume is to ¼ long. The upper glume is much longer, 3 16 to 7 16 long.

Each fertile floret consists of an outer protective bract (lemma), an inner protective bract (palea), and reproductive parts. The lemma is 5 16 to ½ (8 to 13.5 mm) long, is rounded on the back, and has 3 veins. The palea has 2 veins. Bisexual florets have 3 stamens with purplish anthers. Staminate florets may have fewer stamens.

Fruits are seldom produced and when they are they rarely mature. A mature fruit (caryopsis) is 1 16 to long, oblong, and circular or slightly flattened in cross section, with a short beak at the tip.

 
Similar
Species

European common reed (Phragmites australis ssp. americanus) is often found in high densities that exclude all other plants. The leaves are darker in color, often bluish-green. In winter the leaves remain on the culm and do not pull away easily. Culms in the growing season are slightly ridged and dull, not shiny. The inflorescence is more dense and persists throughout the winter. Two other differentiating characteristics, a shorter ligule and a shorter glume, are microscopic and can not be measured in the field.


Distribution Distribution Map  

Sources: 4, 7, 28, 29.


Comments

 


Taxonomy

Family:

Poaceae (grass family)

 

No Rank:

PACMAD clade

 

Subfamily:

Arundinoideae

 

Tribe:

Arundineae

 
Parent

common reed (Phragmites australis)

 
Synonyms

 

 

 

 
Common
Names

American common reed

common reed

common reed grass

giant reed

native common reed

North American common reed

   

 

 

 

 

 

 

 

 

Glossary

caryopsis

The dry, one-seeded, achene-like fruit of a grass, formed from a single carpel, not opening at maturity, and with the fruit wall (pericarp) fused to the seed coat.

 

culm

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

 

glaucous

Pale green or bluish gray due to a whitish, powdery or waxy film, as on a plum or a grape.

 

glume

A chaffy, empty, sterile bract at the base of a grass spikelet. Glumes usually occur in pairs, but occasionally only one is present.

 

lemma

The outer, lowermost of the pair of bracts at the base of the grass floret; it ensheathes the palea.

 

ligule

In grasses, 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.

 

node

The small swelling of the stem from which one or more leaves, branches, or buds originate.

 

palea

The inner, uppermost of the pair of bracts at the base of the grass floret.

 

panicle

A pyramidal inflorescence with a main stem and branches. Flowers on the lower, longer branches mature earlier than those on the shorter, upper ones.

 

rhizome

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

 

sheath

The lower part of the leaf that surrounds the stem.

 

spikelet

The basic unit of inflorescence in grasses, composed of usually two glumes and one or more florets.

       

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Culm

  North American   North American
       

Infructescence

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