categoryZFerns Ferns List 

HARD SHIELD-FERN

Polystichum aculeatum

Male & Buckler-Fern Family [Dryopteridaceae]  
Formerly in: Aspidiaceae Family, which has been deprecated.

Spores:
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category
category8Ferns
status
statusZnative

22nd June 2009, Limestone Paving, Gait Barrows, Silverdale. Photo: © RWD
Roots sheltered in a shallow gryke.


7th June 2014, Limestone Paving, Gait Barrows, Cumbria. Photo: © RWD
Prefers the protection of a gryke.


22nd June 2009, Limestone Paving, Gait Barrows, Silverdale. Photo: © RWD
Alternate golden yellow fronds. Diagnostic feature: The pinnae (leaflets) at the base are less than half the length of the longest in the middle.


22nd June 2009, Limestone Paving, Gait Barrows, Silverdale. Photo: © RWD


22nd June 2009, Limestone Paving, Gait Barrows, Silverdale. Photo: © RWD
Single groove down the stem.


22nd June 2009, Limestone Paving, Gait Barrows, Silverdale. Photo: © RWD
Lower stem has straw-coloured rough hairs.


8th April 2017, Blackbrook, Carr Mill Dam, St. Helens. Photo: © RWD
The obtuse side. Sori yet to form, there are signs of them at the extremities of each pinna (leaf).


8th April 2017, Blackbrook, Carr Mill Dam, St. Helens. Photo: © RWD
Where the pinnules join the main stem the included angle is <90° (an acute angle) (unlike that on the Soft Shield-Fern page where the angle is obtuse (>90° - see angle D)


8th April 2017, Blackbrook, Carr Mill Dam, St. Helens. Photo: © RWD
Unlike the soft 'spikes' at the end (and elsewhere) of the pinnules (leaflets) on Soft Shield-Fern those on Hard Shield-Fern here are much stiffer and sharper and can prick skin.


8th April 2017, Blackbrook, Carr Mill Dam, St. Helens. Photo: © RWD
The crozier or fiddleneck, where the both the main stem has yet to fully un-roll and also the leaves (which are those green things in the middle of the crozier)


7th June 2014, Limestone Paving, Gait Barrows, Cumbria. Photo: © RWD
The parallel alignment of the 'thumbs' to the rachis (main stem) is easier to see from the underside.


22nd June 2009, Limestone Paving, Gait Barrows, Silverdale. Photo: © RWD
Sori on underside of frond.


22nd June 2009, Limestone Paving, Gait Barrows, Silverdale. Photo: © RWD
Sori on underside of frond.


7th June 2014, Limestone Paving, Gait Barrows, Cumbria. Photo: © RWD
Close-up of sori.


Some similarities to : Male-Fern.

Young specimens can be easily mistaken for Holly Fern (Polystichum lonchitis) with which it hybridises but that is singly-pinnate (as opposed to bipinnate for Hard Shield-Fern) and frequently has sori present even when small.

Not to be confused with : Hard-Fern [a plant with similar name]

Hybridises with :

  • Soft Shield-Fern (Polystichum setiferum) to produce Polystichum × bicknellii which is sterile and with intermediate characteristics between the two parents. Frequently found within the range of Soft Shield-Fern.
  • Holly Fern (Polystichum lonchitis) [which is an uncommon [R]] to produce Polystichum × illyricum which occurs with both parents in County Leitrim, and in North and Central Scotland. It too is sterile and intermediate.

Hard Shield-Fern is 1-pinnate to 2-pinnate and hard to the touch with shap points! It is a more upland and northern species than is Soft Shield-Fern (Polystichum setiferum) but occurs less frequently found than that (Polystichum setiferum). It is frequently found in Britain and Ireland.


  Polystichum aculeatum  ⇐ Global Aspect ⇒ Dryopteridaceae  

Distribution
 family8male-fern family8buckler-fern family8Dryopteridaceae

 BSBI maps
genus8Polystichum
Polystichum
(Hard Shield-Ferns)

HARD SHIELD-FERN

Polystichum aculeatum

Male & Buckler-Fern Family [Dryopteridaceae]  
Formerly in: Aspidiaceae Family, which has been deprecated.

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