View source for Dieteria

{{Treatment/ID
|accepted_name=Dieteria
|accepted_authority=Nuttall
|publications={{Treatment/Publication
|title=Trans. Amer. Philos. Soc., n. s.
|place=7: 300. 1840
|year=1840
}}
|basionyms=
|synonyms={{Treatment/ID/Synonym
|name=Aster subg. Hesperastrum
|authority=(A. Gray) A. Gray
}} {{Treatment/ID/Synonym
|name=Machaeranthera subg. Dieteria
|authority=(Nuttall) Greene
}} {{Treatment/ID/Synonym
|name=Machaeranthera (sect. Undefined) ser. Variabiles
|authority=Cronquist & D. D. Keck
}}
|hierarchy=Asteraceae;Asteraceae tribe Astereae;Dieteria
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Astereae]]</div><div class="higher-taxon"><small>genus</small>[[Dieteria]]</div></div>
|etymology=Greek di -, two, and etos, year, alluding to biennial duration of the plants first named by Nuttall
|volume=Volume 20
|mention_page=page 8, 12, 13, 19, 394, 396, 402
|treatment_page=page 395
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals,</b> biennials, or perennials (subshrubs in <i>D. canescens </i>var.<i> ziegleri</i>), 10–100 cm; taprooted. <b>Stems</b> erect to ascending, much branched (when well developed), glabrous or hairy, sometimes stipitate-glandular. <b>Leaves</b> basal and cauline; alternate; usually sessile, sometimes basal and proximal cauline petiolate; blades 1-nerved, ovate, obovate, oblong, lanceolate, oblanceolate, or linear, margins entire or irregularly serrate to dentate (teeth usually spine-tipped), faces glabrous, canescent, or puberulent, often sparsely stipitate-glandular. <b>Heads</b> radiate (sometimes discoid in <i>D. canescens </i>var.<i> shastensis</i>). <b>Involucres</b> turbinate, campanulate, or hemispheric, 6–16 × 6–30 mm. <b>Phyllaries</b> 25–100 in 3–12 series, appressed, spreading, or reflexed, 1-nerved, lanceolate to linear, unequal, bases indurate, apices herbaceous, usually hairy or stipitate-glandular. <b>Receptacles</b> convex, pitted, epaleate. <b>Ray</b> florets 7–60, pistillate, fertile (sterile or 0 in <i>D. canescens </i>var.<i> shastensis</i>); corollas white, blue, violet, or purple. <b>Disc</b> florets 15–200, bisexual, fertile; corollas yellow, tubes shorter than funnelform throats (both glabrous or glabrate), lobes 5, erect, deltate to lanceolate (usually appressed-hairy); style-branch appendages lanceolate. <b>Cypselae</b> linear to obovoid, flattened, smooth or 8–12-ribbed, faces glabrous or ± appressed-hairy; pappi persistent, of 40–50 white to tawny, barbellate, apically attenuate bristles in 1–3 series. <b>x</b> = 4.</span><!--

-->{{Treatment/Body
|distribution=w North America;n Mexico.
|discussion=<p>Species 3 (3 in the flora).</p><!--
--><p><i>Dieteria</i> has often been included in <i>Machaeranthera</i> because of similarities in habit, ray color, chromosome number, and secondary chemistry. The relationship has also been supported by chloroplast DNA evidence (D. R. Morgan and B. B. Simpson 1992). Nuclear ribosomal DNA evidence conflicts with that from chloroplast DNA on the alliances of <i>Dieteria</i>, suggesting reticulate evolution in the ancestors of <i>Machaeranthera</i>, <i>Dieteria</i>, or both (Morgan 2003). In addition, chloroplast DNA and nuclear ribosomal DNA evidence both support a close relationship between <i>Machaeranthera</i> and <i>Oönopsis</i>, and expansion of <i>Machaeranthera</i> to include <i>Dieteria</i> would also have to include <i>Oönopsis</i>, which differs from <i>Machaeranthera</i> in habit, ray color, chromosome number, leaf morphology, and habitat (Morgan and Simpson; Morgan and R. L. Hartman 2003).</p><!--
--><p>Morphologic variation in <i>Dieteria</i> has resulted in the naming of more than 50 species. The treatment adopted here follows that of B. L. Turner (1987b) in recognizing three species and in defining varieties of <i>D. asteroides</i>, <i>D. bigelovii</i>, and <i>D. canescens</i>. Some of the varieties exhibit combinations of the morphologic characteristics of different species and often have been treated as distinct species, most notably <i>D. asteroides </i>var.<i> lagunensis</i> (as <i>Machaeranthera</i> lagunensis), <i>D. bigelovii </i>var.<i> mucronata</i> (as M. mucronata), <i>D. bigelovii </i>var.<i> commixta</i> (as M. commixta), and <i>D. canescens </i>var.<i> leucanthemifolia</i> (as M. leucanthemifolia). Elements of the three species frequently intergrade in areas of contact. Intergradation occurs also among the varieties within each species; it is especially common among the varieties of <i>D. canescens</i>. Turner included a complete synonymy for the species and varieties of <i>Dieteria</i>, while treating the genus as <i>Machaeranthera</i> sect. Hesperastrum.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Phyllaries and peduncles variously hairy (sometimes stipitate-glandular), rarely both prominently stipitate-glandular
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Phyllaries and peduncles both prominently stipitate-glandular
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Phyllaries usually hairy throughout, on both indurate bases and herbaceous apices; apices acute to long-acuminate, 1–6 mm; midstem leaf blades 6–20 mm wide (2–6 mm wide in var. lagunensis)
|[[Dieteria asteroides|Dieteria asteroides]]
|-id=key-0-2
|2
|Phyllaries hairy only on herbaceous apices; apices acute to acuminate, 1–3 mm; midstem leaf blades 1.5–6(–8) mm wide
|[[Dieteria canescens|Dieteria canescens]]
|-id=key-0-3
|3
|Leaves stiffly stipitate-glandular
|[[Dieteria asteroides|Dieteria asteroides]]
|-id=key-0-3
|3
|Leaves glabrous or hairy, but not stiffly stipitate-glandular
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Mid leaf blades lanceolate to oblanceolate and 5–15 mm wide, or phyllary apices long-acuminate (2–6 mm), or both
|[[Dieteria bigelovii|Dieteria bigelovii]]
|-id=key-0-4
|4
|Mid leaf blades linear-lanceolate to linear or linear-oblanceolate (ovate to obovate in var. leucanthemifolia), 1.5–5 mm wide; phyllary apices acute to acuminate (1–3 mm)
|[[Dieteria canescens|Dieteria canescens]]
|}
</div></div><!--

-->{{#Taxon:
name=Dieteria
|author=David R. Morgan
|authority=Nuttall
|rank=genus
|parent rank=tribe
|synonyms=Aster subg. Hesperastrum;Machaeranthera subg. Dieteria;Machaeranthera (sect. Undefined) ser. Variabiles
|basionyms=
|family=Asteraceae
|illustrator=Bee F. Gunn
|distribution=w North America;n Mexico.
|reference=None
|publication title=Trans. Amer. Philos. Soc., n. s.
|publication year=1840
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse_grained_fna_xml/V19-20-21/V20_900.xml
|tribe=Asteraceae tribe Astereae
|genus=Dieteria
}}<!--

-->[[Category:Treatment]][[Category:Asteraceae tribe Astereae]]