western bracken fern

(Pteridium aquilinum var. latiusculum)

Conservation Status
western bracken fern
  IUCN Red List

not listed

     
  NatureServe

N5 - Secure

SNR - Unranked

     
  Minnesota

not listed

     
           
Wetland Indicator Status
     
  Great Plains

FACU - Facultative upland

     
  Midwest

FACU - Facultative upland

     
  Northcentral & Northeast

FACU - Facultative upland

     
           
 
Description
 
 

Western bracken fern is a relatively large, coarse, perennial fern that rises as single, widely spaced leaves (fronds) from an underground, often deep, horizontal stem (rhizome). It often forms large colonies or thickets. The rhizome is slender, long-creeping, and often branched.

There are no aerial stems. Fronds rise directly from the underground rhizome. The fronds are deciduous and erect. They may be 12 to 60 tall, but are usually no more than 36 in height. They are well spaced, 1 to 5 apart.

The leaf stem (stipe) is 6 to 40 long, about the same length as the leafy portion (blade). It is green at first, turning brown later in the season. It is stout, rigid, and hairless. It is shallowly or deeply grooved on the upper surface, making it U-shaped in cross section. It does not have prickles or scales.

The blade is broadly triangular in outline, 8 to 32 long, 10 to 20 wide, and 3 times pinnately divided. It is yellowish-green to dark green and papery or leathery in texture. It is divided into 3 more or less equal parts (branches), a central branch and 2 lateral branches. In shady areas the branches are held more or less parallel to the ground. In sunny areas they are held more vertically.

The branches are pinnately divided divided into 10 or 12 pairs of primary segments or leaflets (pinnae). The pinnae are arranged alternately but closely spaced (subopposite) on the central axis (rachis) of each branch. They spread from the rachis at a 45° to 60° angle. The rachis is green and hairless or sparsely covered on the lower surface with long, soft, straight hairs. There are no prickles or scales on the rachis.

The lowermost pair of pinnae on the terminal branch and sometimes on the lateral branches are larger and more divided than the rest. They are broadly triangular in outline and are each nearly as long as the remaining portion of the branch. They are distinctly stalked. The lower portion of the lowermost pinnae is pinnately divided into leaflets (pinnules) that are clearly separated at the base from the central axis (costa) of the pinna. The upper portion is pinnately divided into subleaflets that are not separated at the base from the costa. Middle and upper pinnae become shorter and less divided as they approach the tip. They are unstalked and narrowly triangular in outline. Middle pinnae are pinnately divided into subleaflets. Uppermost pinnae are merely pinnately lobed or are unlobed. The upper surface of the costa is grooved. The lower surface is sparsely to densely covered with shaggy hairs.

The ultimate segments (subleaflets) are egg-shaped to oblong or linear, narrow, blunt-tipped, and closely spaced. The larger ones are lobed with a terminal lobe that is 2 to 4 times as long as wide. This gives the pinnae the appearance of having a short-tapering tip. The margins of the pinnae are strongly bent backward (reflexed) toward the underside. The margins and lower surface are covered with shaggy hairs. The veins visible on the underside are forked and free, meaning they do not rejoin to form a network but rather extend to a marginal vein beneath the sori. The central axis of the pinnule (costule) is grooved on the upper surface. The U-shaped groove of the costule connects with the groove of the costa, which connects to the groove of the rachis, which connects to the groove of the stipe.

The reproductive structures are born on the underside of the pinnules. There is a nearly continuous line of compact clusters (sora) of spore-bearing cases (sporangia) along the lower margin of the pinnule. The sorus is covered with a protective veil (indusium). The indusium is poorly developed and is hidden by the reflexed margin of the pinnule.

 
     
 

Height

 
 

12 to 36

 
     
 

Similar Species

 
 

Rattlesnake fern (Botrypus virginianus) is much smaller, no more than 18 in height. The pinnules are more finely cut and do not have an extended terminal lobe. The fertile portion is an extension of the stipe that sticks straight up, looking like a separate frond.

Western oak fern (Gymnocarpium dryopteris) is much smaller, no more than 18 in height. It grows in full shade.

 
     
 
Habitat
 
 

Moist to dry. Woodland openings, old pastures, burned over areas, roadsides. Full sun to light shade. Sandy soil.

 
     
 
Biology
 
 

Sporulation

 
 

August to September

 
     
 
Use
 
 

Western bracken fern contains ptaquiloside, a carcinogen, and should not be eaten. It causes stomach cancer in humans when ingested directly. When consumed by grazing animals it is transferred to humans in milk, causing stomach cancer.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 7, 28.

 
  7/9/2012      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Common and widespread

 
         
 
Taxonomy
 
  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Polypodiophytina  
  Class Polypodiopsida (ferns)  
  Subclass Polypodiidae  
 

Order

Polypodiales (true ferns)  
 

Family

Dennstaedtiaceae (bracken)  
 

Genus

Pteridium (bracken ferns)  
  Species Pteridium aquilinum (western bracken fern)  
       
 

Most sources list western bracken fern as a variety, Pteridium aquilinum var. latiusculum. ITIS and NCBI list it a subspecies,Pteridium aquilinum ssp. latiusculum.

 
       
 

Subordinate Taxa

 
 

There are four varieties of Pteridium aquilinum. This is the only variety that occurs in Minnesota.

 
       
 

Synonyms

 
 

Pteridium aquilinum var. champlainense

Pteridium aquilinum ssp. latiusculum

Pteridium latiusculum

 
       
 

Common Names

 
 

eastern bracken

western bracken fern

western brackenfern

 
       

 

 

 

 

 

 

 

 

Glossary

Costa

The central axis of a pinna, to which pinnules are attached.

 

Costule

The midrib of a pinnule.

 

Frond

A large leaf with many divisions: in ferns, the compound leaf, including the stipe and the blade; in mosses, a closely and regularly branched stem resembling a fern leaf; in lichens, a stalkless, leaf-like extension.

 

Indusium

In ferns, a veil covering the cluster (sorus) of spore-producing structures (sporangia).

 

Linear

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

 

Pinna

The primary division of a compound leaf or fern frond.

 

Pinnate

Having the leaflets of a compound leaf arranged on opposite sides of a common stalk.

 

Pinnule

The ultimate segment (individual leaflets) of a twice or more compound leaf or fern frond.

 

Rachis

The main axis of a compound leaf, appearing as an extension of the leaf stalk; the main axis of an inflorescence.

 

Reflexed

Bent backward.

 

Rhizome

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

 

Sorus

A compact cluster of spore-bearing cases or sacs (sporangia) on a fern.

 

Sporangium

A spore bearing structure, as of a fern or moss.

 

Stipe

A supporting stalk-like structure lacking vascular tissue: in fungi, the stalk supporting the mushroom cap; in ferns, the stalk connecting the blade to the rhizome; in flowering plants, the stalk connecting the flower’s ovary to the receptacle; in orchids; the band connecting the pollina with the viscidium.

       
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Plant

  western bracken fern   western bracken fern
       
  western bracken fern   western bracken fern
       

Frond

  western bracken fern   western bracken fern
       

Pinnae

  western bracken fern   western bracken fern
       
  western bracken fern    
       

Pinnules

  western bracken fern   western bracken fern
       

Ultimate Segments

  western bracken fern    
       

Underside

  western bracken fern    
       
       

 

Camera

     
Slideshows
   
  Bracken Fern (Pteridium aquilinum)
Andree Reno Sanborn
 
  Bracken Fern  (Pteridium aquilinum)  

 

slideshow

       
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Other Videos
 
  Bracken Fern.mp4
Darryl Patton
 
   
 
About

Uploaded on Jun 28, 2010

Bracken Ferns have had a long history of being used in herbal medicine for a variety of conditions such as worms. They are however, too toxic for the average person to experiment with until they have gained a great deal of experience. Improper usage will cause internal bleeding.

   
       
  2 Bracken Fern and life cycle.wmv
PalmettoMan Adventures
 
   
 
About

Uploaded on Oct 13, 2011

New River State Park Wagonr Access Fern Nature Trail 2 miles.

   
       
  Bush tucker - Eating bracken fern
James Neill
 
   
 
About

Uploaded on Mar 7, 2010

Jimee shows the kids how to eat fern (one way).

   
       
  Common Bracken (Pteridium aquilinum) - 2012-05-05
W3stlander
 
   
 
About

Published on May 7, 2012

Pteridium aquilinum (bracken or common bracken) is a species of fern occurring in temperate and subtropical regions throughout much of the northern hemisphere.

-----------------

De adelaarsvaren (Pteridium aquilinum) is een varen uit de adelaarsvarenfamilie (Dennstaedtiaceae).

   
       
  HW Plant Challenge 2 Uses of Bracken Fern
luvhambo
 
   
 
About

Published on Jul 17, 2013

The challenge is to show two uses of an herbaceous plant. These are two that I haven't seen done before. Hope you enjoy.

   
       

 

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