western bracken fern

(Pteridium aquilinum var. latiusculum)

Conservation Status
western bracken fern
  IUCN Red List

not listed


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

FACU - Facultative upland


FACU - Facultative upland

  Northcentral & Northeast

FACU - Facultative upland


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.




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.


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




August to September


Pests and Diseases






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 Map



2, 3, 4, 5, 7, 24, 28, 29, 30.








Common and widespread

  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 (leptosporangiate ferns)  


  Suborder Dennstaedtiineae  


Dennstaedtiaceae (bracken)  


Pteridium (brackens)  
  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.




Pteridium aquilinum var. champlainense

Pteridium aquilinum ssp. latiusculum

Pteridium latiusculum


Common Names


common bracken

eagle fern

western bracken fern

western brackenfern












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



The midrib of a pinnule.



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.



Undergarment. In ferns: A veil covering the cluster (sorus) of spore-producing structures (sporangia). In fungi: A skirt-like structure hanging from the cap (receptacle) of a stinkhorn.



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



The primary division of a compound leaf or fern frond.



On a compound leaf, having the leaflets arranged on opposite sides of a common stalk. On a bryophyte, having branches evenly arranged on opposite sides of a stem.



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



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



Bent backward.



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



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



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



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


    western bracken fern   western bracken fern  


    western bracken fern   western bracken fern  
    western bracken fern      


    western bracken fern   western bracken fern  

Ultimate Segments

    western bracken fern      


    western bracken fern      



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



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Other Videos
  Bracken Fern.mp4
Darryl Patton

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

Uploaded on Oct 13, 2011

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

  Bush tucker - Eating bracken fern
James Neill

Uploaded on Mar 7, 2010

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

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

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

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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