View source for Cystopteris fragilis

{{Treatment/ID
|accepted_name=Cystopteris fragilis
|accepted_authority=(Linnaeus) Bernhardi
|publications={{Treatment/Publication
|title=Neues J. Bot.
|place=1(2): 26, plate 2, fig. 9. 1806
|year=1806
}}
|common_names=Brittle fern;fragile fern;cystoptère fragile
|basionyms={{Treatment/ID/Synonym
|name=Polypodium fragile
|authority=Linnaeus
}}
|synonyms={{Treatment/ID/Synonym
|name=Cystopteris dickieana
|authority=Sim
}}{{Treatment/ID/Synonym
|name=Cystopteris fragilis subsp. dickieana
|authority=(Sim) Hylander
}}
|hierarchy=Dryopteridaceae;Cystopteris;Cystopteris fragilis
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Dryopteridaceae]]</div><div class="higher-taxon"><small>genus</small>[[Cystopteris]]</div><div class="higher-taxon"><small>species</small>[[Cystopteris fragilis]]</div></div>
|volume=Volume 2
|mention_page=
|treatment_page=
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="stem growth form or orientation;stem shape;internode height or length or size;petiole base life cycle;hair count"><b>Stems </b>creeping, not cordlike, internodes short, beset with old petiole bases, hairs absent;</span> <span class="statement" id="st-d0_s1" data-properties="scale coloration;scale coloration;scale coloration;scale shape;wall arrangement;wall width;lumina coloration">scales tan to light-brown, lanceolate, radial walls thin, luminae tan.</span> <span class="statement" id="st-d0_s2" data-properties="leaf architecture;leaf arrangement or growth form;leaf some measurement"><b>Leaves </b>monomorphic, clustered at stem apex, to 40 cm, nearly all bearing sori.</span> <span class="statement" id="st-d0_s3" data-properties="petiole coloration;petiole coloration;petiole coloration;petiole coloration;petiole height or length or size;blade variability;base architecture or pubescence"><b>Petiole </b>dark at base, mostly green to straw-colored distally, shorter than or nearly equaling blade, base sparsely scaly.</span> <span class="statement" id="st-d0_s4" data-properties="blade shape;blade shape;blade shape;blade shape;blade width;middle position;apex shape"><b>Blade </b>lanceolate to narrowly elliptic, 1 (–2) -pinnate-pinnatifid, widest at or just below middle, apex acute;</span> <span class="statement" id="st-d0_s5" data-properties="hair count;hair architecture;bulblet count;bulblet architecture">rachis and costae lacking gland-tipped hairs or bulblets;</span> <span class="statement" id="st-d0_s6" data-properties="axil architecture;pinna count;hair architecture">axils of pinnae lacking multicellular, gland-tipped hairs.</span> <span class="statement" id="st-d0_s7" data-properties="pinna orientation;pinna course;margin architecture or shape;margin architecture or shape;margin architecture or shape"><b>Pinnae </b>usually perpendicular to rachis, not curving toward blade apex, margins serrate to sharply dentate;</span> <span class="statement" id="st-d0_s8" data-properties="proximal pinna shape;proximal pinna shape;proximal pinna shape;proximal pinna architecture or shape;pinnule orientation;pinnule size">proximal pinnae pinnatifid to pinnate-pinnatifid, ± equilateral, basiscopic pinnules not enlarged;</span> <span class="statement" id="st-d0_s9" data-properties="pinnule orientation;pinnule architecture;base shape;base shape;base shape;distal pinna shape;distal pinna shape;distal pinna shape">basal basiscopic pinnules sessile, base truncate to obtuse, distal pinnae deltate to ovate.</span> <span class="statement" id="st-d0_s10" data-properties="vein orientation"><b>Veins </b>directed mostly into teeth.</span> <span class="statement" id="st-d0_s11" data-properties="indusium shape;indusium shape;indusium shape;hair architecture"><b>Indusia </b>ovate to lanceolate, without gland-tipped hairs.</span> <span class="statement" id="st-d0_s12" data-properties="spore architecture or shape;spore relief;spore some measurement;2n chromosome count;2n chromosome count"><b>Spores </b>spiny or verrucate, usually 39–60 µm. <b>2n</b> = 168, 252.</span><!--

-->{{Treatment/Body
|habitat=Mostly on cliff faces, also in thin soil over rock
|elevation=0–4500 m
|distribution=Greenland;St. Pierre and Miquelon;Alta.;B.C.;Man.;N.B.;Nfld.;N.W.T.;N.S.;Ont.;P.E.I.;Que.;Sask.;Yukon;Alaska;Calif.;Colo.;Conn.;Idaho;Ill.;Ind.;Iowa;Kans.;Maine;Mass.;Mich.;Minn.;Mont.;Nebr.;Nev.;N.H.;N.Mex.;N.Y.;N.Dak.;Ohio;Oreg.;Pa.;S.Dak.;Tex.;Utah;Vt.;Wash.;Wis.;Wyo.;worldwide.
|discussion=<p>Cystopteris fragilis is most often confused with C. tenuis in the east and C. reevesiana in the southwest. Habitat and geography, as well as the morphologic features discussed in the key, usually serve to separate these taxa. For instance, C. fragilis is more likely to be found on cliffs whereas the other species prefer boulders and soil (C. fragilis occurs at higher elevations and/or latitudes than the other species). These distinctions can be confounded when C. fragilis forms hybrids with sympatric species. Sterile pentaploid plants have been discovered where C. fragilis overlaps with C. laurentiana, tetraploid hybrids are likely where C. fragilis occurs with C. tenuis, and triploids may form where C. fragilis is found with C. reevesiana. Even after segregating relatively distinct elements such as Cystopteris protrusa, C. reevesiana, and C. tenuis, and identifying sterile hybrids, C. fragilis still remains a polymorphic and complex taxon that probably contains a number of natural, cryptic evolutionary units. For example, morphologically distinct hexaploid cytotypes have been reported (C. H. Haufler and M. D. Windham 1991). These occur as isolated and disjunct populations in Ontario, Alaska, Arizona, Colorado, Montana, and Wyoming. Isozymic profiles of each of these populations indicate that the hexaploids are polyphyletic and should not be accorded species status.</p><!--
--><p>The presence of verrucate spores (as opposed to the normal spiny spores) has been used to circumscribe Cystopteris dickieana. Although genetic analyses have not been undertaken, we think the verrucate spore is probably a recessive feature controlled by one or a few genes. While present at low frequency in much of the range of C. fragilis, verrucate spores are particularly prominent in the Great Plains. Perhaps in this region the genetic combinations specifying verrucate spores have been fixed. Following R. F. Blasdell (1963), C. dickieana is also considered here to be conspecific with C. fragilis because (1) early stages in the development of spiny spores can appear verrucate (A. C. Jermy and L. Harper 1971), (2) the hexaploid cytotypes discussed above always have verrucate spores, regardless of their parentage, (3) individuals with verrucate spores can be found in populations that are otherwise uniformly spiny-spored, and (4) individuals and populations that have verrucate spores are not otherwise (morphologically, ecologically, or genetically) distinct from those that have spiny spores.</p><!--
--><p>Especially in the western portion of its North American range (British Columbia, Washington, Montana, Idaho, Oregon, California), Cystopteris fragilis appears to be developing morphologically and ecologically distinctive variants. Hybrid individuals with aborted spores have been discovered, and plants from these areas increasingly tend to grow on both soil and rock and to have slightly different morphologies on the two substrates. These variants intergrade, however, and are not sufficiently distinct to warrant species status. This polymorphic polyploid is probably actively speciating at the tetraploid level, perhaps through gene silencing (C. R. Werth and M. D. Windham 1991).</p>
|tables=
|references=
}}<!--

--><!--

-->{{#Taxon:
name=Cystopteris fragilis
|author=
|authority=(Linnaeus) Bernhardi
|rank=species
|parent rank=genus
|synonyms=Cystopteris dickieana;Cystopteris fragilis subsp. dickieana
|basionyms=Polypodium fragile
|family=Dryopteridaceae
|habitat=Mostly on cliff faces, also in thin soil over rock
|elevation=0–4500 m
|distribution=Greenland;St. Pierre and Miquelon;Alta.;B.C.;Man.;N.B.;Nfld.;N.W.T.;N.S.;Ont.;P.E.I.;Que.;Sask.;Yukon;Alaska;Calif.;Colo.;Conn.;Idaho;Ill.;Ind.;Iowa;Kans.;Maine;Mass.;Mich.;Minn.;Mont.;Nebr.;Nev.;N.H.;N.Mex.;N.Y.;N.Dak.;Ohio;Oreg.;Pa.;S.Dak.;Tex.;Utah;Vt.;Wash.;Wis.;Wyo.;worldwide.
|reference=None
|publication title=Neues J. Bot.
|publication year=1806
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/287ef3db526bd807d435a3c7423ef2df1e951227/V2/V2_806.xml
|genus=Cystopteris
|species=Cystopteris fragilis
|2n chromosome count=252;168
|apex shape=acute
|axil architecture=multicellular
|base architecture or pubescence=scaly
|base shape=truncate;obtuse
|blade shape=1(-2)-pinnate-pinnatifid;lanceolate;narrowly elliptic
|blade variability=equaling
|blade width=widest
|bulblet architecture=gland-tipped
|bulblet count=lacking
|distal pinna shape=deltate;ovate
|hair architecture=gland-tipped;gland-tipped;gland-tipped
|hair count=lacking;absent
|indusium shape=ovate;lanceolate
|internode height or length or size=short
|leaf architecture=monomorphic
|leaf arrangement or growth form=clustered
|leaf some measurement=0cm;40cm
|lumina coloration=tan
|margin architecture or shape=serrate;sharply dentate
|middle position=middle
|petiole base life cycle=old
|petiole coloration=mostly green;straw-colored
|petiole height or length or size=shorter
|pinna count=lacking
|pinna course=not curving
|pinna orientation=perpendicular
|pinnule architecture=sessile
|pinnule orientation=basiscopic;basiscopic
|pinnule size=not enlarged
|proximal pinna architecture or shape=equilateral
|proximal pinna shape=pinnatifid;pinnate-pinnatifid
|scale coloration=tan;light-brown
|scale shape=lanceolate
|spore architecture or shape=spiny
|spore relief=verrucate
|spore some measurement=39um;60um
|stem growth form or orientation=creeping
|stem shape=not cordlike
|vein orientation=directed
|wall arrangement=radial
|wall width=thin
}}<!--

-->[[Category:Treatment]][[Category:Cystopteris]]