View source for Spiranthes cernua

{{Treatment/ID
|accepted_name=Spiranthes cernua
|accepted_authority=(Linnaeus) Richard
|publications={{Treatment/Publication
|title=De Orchid. Eur.,
|place=37. 1817
|year=1817
}}
|special_status={{Treatment/ID/Special_status
|code=F
|label=Illustrated
}}{{Treatment/ID/Special_status
|code=E
|label=Endemic
}}
|basionyms={{Treatment/ID/Basionym
|name=Ophrys cernua
|authority=Linnaeus
|rank=species
|publication_title=Sp. Pl.
|publication_place=2: 946. 1753
}}
|synonyms={{Treatment/ID/Synonym
|name=Ibidium cernuum
|authority=(Linnaeus) House
|rank=species
}}
|hierarchy=Orchidaceae;Orchidaceae subfam. Orchidoideae;Orchidaceae tribe Cranichideae;Orchidaceae (tribe Cranichideae) subtribe Spiranthinae;Spiranthes;Spiranthes cernua
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Orchidaceae]]</div><div class="higher-taxon"><small>subfamily</small>[[Orchidaceae subfam. Orchidoideae]]</div><div class="higher-taxon"><small>tribe</small>[[Orchidaceae tribe Cranichideae]]</div><div class="higher-taxon"><small>subtribe</small>[[Orchidaceae (tribe Cranichideae) subtribe Spiranthinae]]</div><div class="higher-taxon"><small>genus</small>[[Spiranthes]]</div><div class="higher-taxon"><small>species</small>[[Spiranthes cernua]]</div></div>
|volume=Volume 26
|mention_page=page 532, 533, 534, 538, 539, 541, 542
|treatment_page=page 540
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="whole_organism some measurement;whole_organism growth form"><b>Plants </b>10–50 cm.</span> <span class="statement" id="st-d0_s1" data-properties="root quantity;root size;root orientation;root diameter"><b>Roots </b>few, slender to tuberously thickened, horizontally spreading to descending, mostly to 1 cm diam.</span> <span class="statement" id="st-d0_s2" data-properties="leaf duration;leaf orientation;basal leaf life cycle;basal leaf duration"><b>Leaves </b>persisting through anthesis or fugaceous, basal, sometimes on proximal portion of stem, ascending to spreading (flaccidly so because of membranaceous blades with thickened midribs);</span> <span class="statement" id="st-d0_s3" data-properties="petiole size;petiole width">petiole usually slender, less than 6 mm wide;</span> <span class="statement" id="st-d0_s4" data-properties="blade shape;blade shape;blade shape;blade shape;blade shape;blade shape;blade length;blade width">blade linearlanceolate to linear-oblanceolate, oblanceolate, obovate, or elliptic, to 26 × 2 cm.</span> <span class="statement" id="st-d0_s5" data-properties="spike arrangement;spike quantity;cycle architecture or fragility;cycle arrangement or course;cycle quantity"><b>Inflorescences:</b> spikes very tightly to rather loosely spiraled, 3–4 flowers per cycle of spiral, rarely in loose spiral with 5 or more flowers per cycle;</span> <span class="statement" id="st-d0_s6" data-properties="rachis pubescence;trichome architecture or shape;gland architecture">rachis moderately to densely pubescent, some trichomes capitate, glands obviously stalked.</span> <span class="statement" id="st-d0_s7" data-properties="flower coloration;flower coloration;flower coloration;flower coloration;flower orientation;base orientation;base shape;base architecture;claw shape;angle position"><b>Flowers </b>white to ochroleucous, creamy, or ivory, occasionally green or rarely yellowish, nodding only at base of perianth or occasionally ascending, urceolate to gaping, base usually appearing only slightly inflated, claw of lip at low (less than 30°) angle to lamina, or occasionally not opening;</span> <span class="statement" id="st-d0_s8" data-properties="sepal fusion;sepal some measurement">sepals distinct to base, 6–12 mm;</span> <span class="statement" id="st-d0_s9" data-properties="lateral sepal orientation;apex orientation;apex course;apex orientation">lateral sepals appressed to spreading, apices incurved or sometimes straight, sometimes arching above flower;</span> <span class="statement" id="st-d0_s10" data-properties="petal some measurement;apex shape;apex width;apex shape">petals linearlanceolate, 6–12 mm, apex acute to obtuse, occasionally broad and liplike;</span> <span class="statement" id="st-d0_s11" data-properties="lip coloration;lip shape;lip size;lip length;lip width;base shape;base shape;base shape;base shape;base shape;base shape;margin shape;margin shape;margin architecture or shape;apex shape;apex pubescence">lip often yellow centrally, ovate to oblong in general outline, usually constricted at middle, 6–10.5 × 2–7.5 mm, base ± prominently dilated, suborbiculate, orbiculate, or linear, margins crenulate, lacerate or sometimes entire, apex acute to rounded distally, glabrous;</span> <span class="statement" id="st-d0_s12" data-properties="vein quantity;branch arrangement">veins several, branches parallel;</span> <span class="statement" id="st-d0_s13" data-properties="basal callus orientation;basal callus prominence;basal callus shape;basal callus size;basal callus some measurement;lip prominence">basal calli usually incurved, prominent to conic, small, mostly 0.5–1.2 mm, or sometimes lip undifferentiated from petals;</span> <span class="statement" id="st-d0_s14" data-properties="viscidium arrangement or course or shape">viscidia linear to linearlanceolate;</span> <span class="statement" id="st-d0_s15" data-properties="ovary some measurement">ovary 3–14 mm.</span> <span class="statement" id="st-d0_s16" data-properties=""><b>Seeds </b>polyembryonic, often also monoembryonic, rarely wholly monoembryonic;</span> <span class="statement" id="st-d0_s17" data-properties="embryo development;embryo architecture;embryo arrangement">typically showing irregularities such as embryos developing through or outside testa or naked embryos mixed with whole seed.</span> <span class="statement" id="st-d0_s18" data-properties="seed architecture;seed architecture;seed architecture;2n chromosome quantity;2n chromosome quantity">2n = 45, 60.</span><!--

-->{{Treatment/Body
|phenology=Flowering late Aug–Nov.
|habitat=Wet to dry open sites in fens, marshes, meadows, swales, dunes, prairies, open woodlands, riverbanks, shores, ditches, roadsides, old fields, cemeteries, lawns
|elevation=0–1800 m
|distribution=N.B.;N.S.;Ont.;P.E.I.;Que.;Ala.;Ark.;Conn.;Ga.;Ill.;Ind.;Iowa;Kans.;Ky.;La.;Maine;Md.;Mass.;Mich.;Minn.;Miss.;Mo.;Nebr.;N.H.;N.J.;N.Y.;N.C.;Ohio;Okla.;Pa.;R.I.;S.C.;Tenn.;Tex.;Vt.;Va.;W.Va.;Wis.
|discussion=<p>Spiranthes cernua is a facultatively agamospermic polyploid compilospecies in which unidirectional gene flow from related diploids generates a wide range of novel forms and races. Chromosomal segregation has given rise to some forms that very nearly approximate the diploid donor, and meiotic irregularities produce peloria and other abnormal conditions. Apomixis then permits reproduction in pure lines, some of which are so distinctive as to appear to be species. Determination of this and related species is consequently often challenging.</p><!--
--><p>Adventitious embryony in this species commonly gives rise to polyembryonic seeds and seeds exhibiting irregularities such as embryos erupting through or developing outside the testa and naked embryos lacking testae. Often a capsule contains a mixture of polyembryonic and monoembryonic seeds. Rarely all or most seed is monoembryonic, yet irregularities can still be seen.</p><!--
--><p>Polyembryony is also characteristic of Spiranthes casei and S. parksii, species that are probably derivatives of S. cernua. For the most part, at least, related diploids and all other species are strictly sexual and characterized by wholly monoembryonic seed. Some indication of apomixis and polyembryony in S. magnicamporum, S. ochroleuca, and S. odorata in the northeastern portion of the range of the complex has been reported (P. M. Catling 1981, 1982), but the difficulty in distinguishing between diploid donors and tetraploid chromosomal segregates makes interpretation difficult (C. J. Sheviak 1982, 1991). In particular, the range of S. odorata northward along the Atlantic Coast is uncertain. Plants that appear typical of S. odorata in all respects but with polyembryonic seed occur from Virginia northward and quickly replace monoembryonic plants toward the north. Such plants from as far south as Virginia, however, have proven to be tetraploids and furthermore to assume morphology typical of S. cernua when grown away from the Coast.</p><!--
--><p>Gene flow from Spiranthes magnicamporum generates cytogenetically based peloria, a common element in portions of the prairie region. Most commonly differentiation of the lip is suppressed, but in some forms the petals are elaborated and approach the lip in form. Additionally, buds may fail to open and a functional column may be lacking, yet seed is produced apomictically. See the discussion under 16. S. parksii.</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Spiranthes cernua
|authority=(Linnaeus) Richard
|rank=species
|parent rank=genus
|synonyms=Ibidium cernuum
|basionyms=Ophrys cernua
|family=Orchidaceae
|phenology=Flowering late Aug–Nov.
|habitat=Wet to dry open sites in fens, marshes, meadows, swales, dunes, prairies, open woodlands, riverbanks, shores, ditches, roadsides, old fields, cemeteries, lawns
|elevation=0–1800 m
|distribution=N.B.;N.S.;Ont.;P.E.I.;Que.;Ala.;Ark.;Conn.;Ga.;Ill.;Ind.;Iowa;Kans.;Ky.;La.;Maine;Md.;Mass.;Mich.;Minn.;Miss.;Mo.;Nebr.;N.H.;N.J.;N.Y.;N.C.;Ohio;Okla.;Pa.;R.I.;S.C.;Tenn.;Tex.;Vt.;Va.;W.Va.;Wis.
|reference=None
|publication title=De Orchid. Eur.,
|publication year=1817
|special status=Illustrated;Endemic
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V26/V26_1100.xml
|subfamily=Orchidaceae subfam. Orchidoideae
|tribe=Orchidaceae tribe Cranichideae
|subtribe=Orchidaceae (tribe Cranichideae) subtribe Spiranthinae
|genus=Spiranthes
|species=Spiranthes cernua
|2n chromosome quantity=60;45
|angle position=low
|apex course=straight
|apex orientation=arching;incurved
|apex pubescence=glabrous
|apex shape=acute;rounded
|apex width=broad
|basal callus orientation=incurved
|basal callus prominence=prominent
|basal callus shape=conic
|basal callus size=small
|basal callus some measurement=0.5mm;1.2mm
|basal leaf duration=fugaceous
|basal leaf life cycle=anthesis
|base architecture=gaping
|base orientation=ascending
|base shape=linear;orbiculate;linear;orbiculate;suborbiculate;dilated;urceolate
|blade length=0cm;26cm
|blade shape=elliptic;obovate;elliptic;obovate;oblanceolate;linear-oblanceolate
|blade width=0cm;2cm
|branch arrangement=parallel
|claw shape=inflated
|cycle architecture or fragility=loose
|cycle arrangement or course=spiral
|cycle quantity=5
|embryo architecture=naked
|embryo arrangement=mixed
|embryo development=developing
|flower coloration=white;ochroleucous creamy or ivory occasionally green or rarely yellowish
|flower orientation=nodding
|gland architecture=stalked
|lateral sepal orientation=appressed;spreading
|leaf duration=persisting
|leaf orientation=ascending;spreading
|lip coloration=yellow
|lip length=6mm;10.5mm
|lip prominence=undifferentiated
|lip shape=ovate;oblong
|lip size=constricted
|lip width=2mm;7.5mm
|margin architecture or shape=entire
|margin shape=lacerate;crenulate
|ovary some measurement=3mm;14mm
|petal some measurement=6mm;12mm
|petiole size=slender
|petiole width=0mm;6mm
|rachis pubescence=pubescent
|root diameter=0cm;1cm
|root orientation=horizontally spreading;descending
|root quantity=few
|root size=slender;tuberously thickened
|seed architecture=monoembryonic;monoembryonic;polyembryonic
|sepal fusion=distinct
|sepal some measurement=6mm;12mm
|spike arrangement=spiraled
|spike quantity=3;4
|trichome architecture or shape=capitate
|vein quantity=several
|viscidium arrangement or course or shape=linear
|whole_organism growth form=plant
|whole_organism some measurement=10cm;50cm
}}<!--

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