View source for Tripleurospermum

{{Treatment/ID
|accepted_name=Tripleurospermum
|accepted_authority=Schultz-Bipontinus
|publications={{Treatment/Publication
|title=Tanaceteen,
|place=31. 1844
|year=1844
}}
|common_names=Mayweed
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Anthemideae;Tripleurospermum
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Anthemideae]]</div><div class="higher-taxon"><small>genus</small>[[Tripleurospermum]]</div></div>
|etymology=Greek tri- , three-, pleuro- , ribbed, and sperma, seed, alluding to strongly 3-ribbed cypselae
|volume=Volume 19
|mention_page=page 31, 488, 541, 550
|treatment_page=page 548
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="whole-organism duration;whole-organism some measurement;whole-organism duration;whole-organism duration"><b>Annuals,</b> biennials, or perennials, 5–80 cm (taprooted; scentless or nearly so).</span> <span class="statement" id="st-d0_s1" data-properties="stem quantity;stem orientation;stem orientation;stem growth form;stem architecture;stem architecture;stem pubescence;stem pubescence"><b>Stems </b>1–5+, usually erect or ascending, sometimes procumbent, branched or simple, glabrous or sparsely hairy (hairs basifixed).</span> <span class="statement" id="st-d0_s2" data-properties=""><b>Leaves </b>(not marcescent) basal (usually withering by flowering) and cauline;</span> <span class="statement" id="st-d0_s3" data-properties="leaf position;leaf position;leaf architecture;leaf architecture">petiolate or sessile;</span> <span class="statement" id="st-d0_s4" data-properties="blade shape;blade shape;ultimate margin shape;ultimate margin shape;face pubescence;face pubescence">blades oblong, 1–3-pinnately lobed, ultimate margins crenate or serrate, faces glabrous or sparsely hairy.</span> <span class="statement" id="st-d0_s5" data-properties="head architecture or arrangement;head arrangement;head arrangement;array architecture"><b>Heads </b>radiate [discoid or disciform], borne singly or in corymbiform arrays.</span> <span class="statement" id="st-d0_s6" data-properties="involucre shape;involucre diameter"><b>Involucres </b>hemispheric to patelliform, 8–12+ mm diam.</span> <span class="statement" id="st-d0_s7" data-properties="phyllary duration;phyllary quantity;phyllary fusion;phyllary shape;phyllary size;series quantity;margin texture;apex texture"><b>Phyllaries </b>persistent, 28–60+ in 2–5 series, distinct, broadly ovate, unequal to subequal, margins and apices (pale to dark-brown or black) narrowly to widely scarious (abaxial faces glabrous).</span> <span class="statement" id="st-d0_s8" data-properties="receptacle shape;receptacle architecture"><b>Receptacles </b>convex to conic (± solid), epaleate.</span> <span class="statement" id="st-d0_s9" data-properties="ray-floret atypical quantity;ray-floret quantity;ray-floret architecture;ray-floret reproduction"><b>Ray-</b>florets [0] 10–34+, pistillate, fertile;</span> <span class="statement" id="st-d0_s10" data-properties="corolla coloration;lamina shape">corollas white [seldom pinkish], laminae mostly oblong.</span> <span class="statement" id="st-d0_s11" data-properties="disc-floret quantity;disc-floret reproduction;disc-floret reproduction"><b>Disc-</b>florets 300–500, bisexual, fertile;</span> <span class="statement" id="st-d0_s12" data-properties="corolla coloration;tube shape;throat shape;lobe quantity;lobe shape">corollas yellow [greenish], tubes cylindric (sessile-glandular), throats narrowly campanulate (cylindric or compressed), lobes 5, deltate (with resin sacs).</span> <span class="statement" id="st-d0_s13" data-properties="cypsela shape;cypsela shape;rib quantity;face relief;face relief;face pubescence"><b>Cypselae </b>trigonous, ± compressed (apices truncate), ribs 3–5 (0–2 abaxial, 2 lateral, 1 adaxial, usually whitish, relatively thick, smooth), faces often rugose or tuberculate abaxially and between ribs and glabrous (pericarps sometimes with myxogenic cells and usually 2–3, sometimes 1–5, abaxial-apical resin sacs; embryo-sac development tetrasporic);</span> <span class="statement" id="st-d0_s14" data-properties="">pappi 0 [coroniform or each an adaxial auricle].</span> <span class="statement" id="st-d0_s15" data-properties="pappus presence;x chromosome quantity">x = 9.</span><!--

-->{{Treatment/Body
|distribution=North America;Eurasia;North Africa;in New Zealand;one species widespread as a weed
|discussion=<p>Species ca. 40 (2 in the flora).</p><!--
--><p>Tripleurospermum often has been included within Matricaria. It is distinguished from the latter by 3-ribbed cypselae with 2 abaxial-apical resin sacs versus 5-ribbed cypselae without apical sacs, and by production of 7-glycoside flavonols versus 3-glycosides (K. Bremer and C. J. Humphries 1993). C. Oberprieler (2001) showed that Tripleurospermum is closely related to Anthemis in the strict sense and not to Matricaria. This is supported by the tetrasporic embryo sac shared by Tripleurospermum and Anthemis (versus monosporic in Matricaria and other anthemid genera), similarity of karyotype, and the presence in both genera of matricaria ester in the polyacetylene pathway, otherwise unknown in the tribe.</p><!--
--><p>Although W. L. Applequist (2002) favored a single species, Tripleurospermum maritimum, for the three taxa (as subspecies) present in North America, based in large parts on the findings of A. Vaarama (1953) on crossing ability among these taxa, on the existence of hybrid populations, and on the (mistaken) supposition that they form a polyploid series, some recent authors (e.g., Q. O. N. Kay 1976b, 1994; A. R. Clapham et al. 1987; E. G. Voss 1972–1996, vol. 3) have maintained two species based on morphologic characters, notably perennial versus annual habit, spacing of ribs (closer versus wider), elongate versus ± circular resin sacs on cypselae, relative infrequency of hybrid populations, and relative sterility of some hybrid individuals, as well as both species harboring diploid and tetraploid populations (Clapham et al.; Kay 1994). Success in interbreeding among plants does not always indicate conspecific status. In North America, authors such as M. L. Fernald (1950) and H. A. Gleason and A. Cronquist (1991) treated (in Matricaria) T. inodorum and T. maritimum subsp. maritimum as a single species with varieties or as a single entity, resulting in confusion about the distinctness of the two taxa in their ranges of introduction, and also difficulty in recognizing the presence of T. inodorum in areas where T. maritimum subsp. maritimum is present in coastal northeastern United States (e.g., D. W. Magee and H. E. Ahles 1999). N. N. Tzvelev (2002b) segregated the subspecies of T. maritimum as species; under his scheme, three species are present in North America: T. inodorum, T. maritimum in the strict sense, and T. hookeri (= T. maritimum subsp. phaeocephalum). Pending further taxonomic work on this complex, I have here retained the taxonomy (except generic assignment) adopted by Kay (1976b), with two species, one including two subspecies.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Annuals (sometimes biennials or perennials); stems ascending to erect; ultimate leaf lobes not fleshy; cypselae: ribs separated by at least 1/3 their widths, resin glands ± circular (lengths mostly 1–1.5 times widths); scarious margins of phyllaries light brown, relatively narrow; cultivated and waste grounds
|[[Tripleurospermum inodorum|Tripleurospermum inodorum]]
|-id=key-0-1
|1
|Perennials (or biennials); stems usually procumbent, sometimes ascending; ultimate leaf lobes fleshy; cypselae: ribs contiguous or separated by less than 1/4 their widths, resin glands ± elongate (lengths 2+ times widths); scarious margins of phyllaries pale to dark brown, relatively wide; open coastal habitats
|[[Tripleurospermum maritimum|Tripleurospermum maritimum]]
|}
</div></div><!--

-->{{#Taxon:
name=Tripleurospermum
|author=Luc Brouillet
|authority=Schultz-Bipontinus
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Asteraceae
|illustrator=Linny Heagy
|illustration copyright=Flora of North America Association
|distribution=North America;Eurasia;North Africa;in New Zealand;one species widespread as a weed
|reference=None
|publication title=Tanaceteen,
|publication year=1844
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V19-20-21/V19_955.xml
|tribe=Asteraceae tribe Anthemideae
|genus=Tripleurospermum
|apex texture=scarious
|array architecture=corymbiform
|blade shape=lobed;oblong
|corolla coloration=yellow;white
|cypsela shape=compressed;trigonous
|disc-floret quantity=300;500
|disc-floret reproduction=fertile;bisexual
|face pubescence=glabrous;hairy;glabrous
|face relief=tuberculate;rugose
|head architecture or arrangement=radiate
|head arrangement=in corymbiform arrays;singly
|involucre diameter=8mm;12mm
|involucre shape=hemispheric;patelliform
|lamina shape=oblong
|leaf architecture=sessile;petiolate
|leaf position=cauline;basal
|lobe quantity=5
|lobe shape=deltate
|margin texture=scarious
|pappus presence=absent
|phyllary duration=persistent
|phyllary fusion=distinct
|phyllary quantity=28;60
|phyllary shape=ovate
|phyllary size=unequal;subequal
|ray-floret architecture=pistillate
|ray-floret atypical quantity=0
|ray-floret quantity=10;34
|ray-floret reproduction=fertile
|receptacle architecture=epaleate
|receptacle shape=convex;conic
|rib quantity=3;5
|series quantity=2;5
|stem architecture=simple;branched
|stem growth form=procumbent
|stem orientation=ascending;erect
|stem pubescence=hairy;glabrous
|stem quantity=1;5
|throat shape=campanulate
|tube shape=cylindric
|ultimate margin shape=serrate;crenate
|whole-organism duration=perennial;biennial;annual
|whole-organism some measurement=5cm;80cm
|x chromosome quantity=9
}}<!--

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