View source for Stephanomeria

{{Treatment/ID
|accepted_name=Stephanomeria
|accepted_authority=Nuttall
|publications={{Treatment/Publication
|title=Trans. Amer. Philos. Soc., n. s.,
|place=7: 427. 1841
|year=1841
}}
|common_names=Stickweed;wirelettuce;skeletonweed
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Cichorieae;Stephanomeria
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Cichorieae]]</div><div class="higher-taxon"><small>genus</small>[[Stephanomeria]]</div></div>
|etymology=Greek stephanos, crown, wreath, and meris, part, presumably alluding to appearance of plumose bristles of pappus
|volume=Volume 19
|mention_page=page 219, 349, 351, 354, 360, 361, 370
|treatment_page=page 350
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals,</b> 10–200 cm, taprooted, or perennials, 10–100 cm, with deeply seated, woody caudices or stout or slender, creeping rhizomes. <b>Stems</b> (1–8) erect, simple or branched, usually glabrous, sometimes hairy (especially when young). <b>Leaves</b> basal (withered at flowering in annuals and some perennials) and/or cauline (much reduced, bractlike in annuals and some perennials); usually sessile; blades linear to oblong, oblanceolate, or spatulate, usually runcinate, margins usually pinnately lobed (spinulose-tipped in <i>S. parryi</i>), sometimes entire or toothed (<i>S. lactucina</i>, <i>S. tenuifolia</i>, and <i>S. fluminea</i>) (faces glabrous, puberulent, or tomentose); distal bractlike (to 45 mm in <i>S. fluminea</i>). <b>Heads</b> borne singly or clustered (in paniculiform arrays in some subspecies of <i>S. exigua</i>). <b>Peduncles</b> not inflated distally, sometimes bracteate. <b>Calyculi</b> of 3–5, unequal bractlets (more numerous in some perennials; not distinguishable in <i>S. cichoriacea</i>), appressed or reflexed (some annuals). <b>Involucres</b> ± cylindric to turbinate, 2–3(–5+) mm diam. <b>Phyllaries</b> usually 5–12 in 1 series, equal (20–25 in 2–3 series, unequal in <i>S. cichoriacea</i>, usually glabrous, rarely puberulent, densely stipitate-glandular in <i>S. exigua </i>subsp.<i> deanei</i>). <b>Receptacles</b> flat, usually smooth (pitted in <i>S. cichoriacea</i>), glabrous, epaleate. <b>Florets</b> (4–)5–16; corollas usually pink or lavender, sometimes white (annuals often purple-tinged abaxially). <b>Cypselae</b> light tan to dark brown, columnar, sometimes slightly curved, 5-angled, apices truncate, faces equal, sometimes with ribs between faces, each face with central, narrow, longitudinal groove or furrow (not grooved in <i>S. virgata</i>), otherwise smooth or bumpy to tuberculate, usually glabrous (scaberulous in <i>S. fluminea</i>); pappi persistent (or only widened bases of bristles persistent after distal portions break off) or falling, of 5–40, distinct or basally connate in groups, white to tan, wholly or distally plumose bristles in 1 series. <b>x</b> = 8.</span><!--

-->{{Treatment/Body
|distribution=w North America;n Mexico.
|discussion=<p>Species 16 (14 in the flora).</p><!--
--><p>Because all the species of <i>Stephanomeria</i> have not previously been examined at one time, the present treatment provides the first unified picture of their variability, ecologic specializations, and geographic distributions. The genus includes six annual species (all in the flora) and ten perennial species (eight in the flora, one in the mountains of northern Baja California, and one known only from Guadalupe Island, Mexico).</p><!--
--><p>Taxonomic distinctions among annual species of <i>Stephanomeria</i> did not become evident until their morphology and geographic distributions were correlated with their chromosome numbers and reproductive compatibilities (L. D. Gottlieb 1971, 1972). The same studies also provided an hypothesis that satisfactorily accounted for their variability. Studies showed that <i>S. exigua</i> and <i>S. virgata</i> differed for a relatively large number of characters and that other annual species originated from genetic segregates that were formed by hybridization, at both diploid and tetraploid levels, as well as directly from <i>S. exigua</i>.</p><!--
--><p><i>Stephanomeria exigua</i> has five subspecies; <i>S. virgata</i> has two. Within each species, the subspecies share numerous morphologic features as well as chromosomal karyotype. They are recognized as polytypic because reproductive compatibility between any pair of subspecies of <i>S. exigua</i> or between subspecies of <i>S. virgata</i> is substantially higher than is the compatibility between the two species. The two species appear to represent a fundamental phylogenetic divergence within annuals; nevertheless their different features are combined in different ways in <i>S. elata</i> and <i>S. diegensis</i>.</p><!--
--><p><i>Stephanomeria paniculata</i> and <i>S. malheurensis</i> probably evolved more or less directly from <i>S. exigua </i>subsp.<i> coronaria</i>. The speciation process that gave rise to <i>S. malheurensis</i> (L. D. Gottlieb 1978) has been examined in a series of studies (Gottlieb 1973b, 1977, 1979; S. Brauner and Gottlieb 1987, 1989). The origin of the highly self-pollinating <i>S. paniculata</i> may have been similar but much less evidence is available. <i>Stephanomeria malheurensis</i> has served as a model for reintroduction of a species back into its original habitat after local extinction, in its case by competition from invasive cheatgrass (<i>Bromus tectorum</i>).</p><!--
--><p>Information about evolution and speciation is not so available for the perennials as for the annuals. Treatment of perennials is based almost entirely on examination of herbarium specimens plus published information describing their chromosome numbers. Although little is known about phylogenetic relationships among perennial species of <i>Stephanomeria</i>, a recent DNA sequencing study of nuclear rDNA (J. Lee et al. 2002) showed that the genus does not include either <i>Munzothamnus blairii</i> (previously S. blairii) or <i>Pleiacanthus spinosus</i> (previously <i>S. spinosa</i>). Without them, <i>Stephanomeria</i> is a well-supported, monophyletic group of species.</p><!--
--><p>The DNA analysis suggested that <i>Stephanomeria tenuifolia</i>, <i>S. runcinata</i>, <i>S. fluminea</i>, and <i>S. thurberi</i> comprise a subclade. Those four species are perennial and all have fully plumose, white pappus bristles. They differ markedly in their ecologic specializations, as indicated in their treatments below. The DNA studies also showed a very close relationship between <i>S. malheurensis</i> and <i>S. exigua </i>subsp.<i> coronaria</i> consistent with results of previous studies (cited above). It is to be hoped that taxonomic information presented below will make species of <i>Stephanomeria</i> more easily accessible to continuing studies.</p>
|tables=
|references={{Treatment/Reference
|id=gottlieb1971a
|text=Gottlieb, L. D. 1971. Evolutionary relationships in the outcrossing diploid annual species of Stephanomeria (Compositae). Evolution 25: 312–329.
}}{{Treatment/Reference
|id=gottlieb1972a
|text=Gottlieb, L. D. 1972. A proposal for classification of the annual species of Stephanomeria (Compositae). Madroño 21: 463–481.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Perennials
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Annuals
|[[#key-0-9| > 9]]
|-id=key-0-2
|2
|Florets 8–16
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Florets 4–6
|[[#key-0-6| > 6]]
|-id=key-0-3
|3
|Calyculi 0 (phyllaries 20–25, unequal); receptacles pitted
|[[Stephanomeria cichoriacea|Stephanomeria cichoriacea]]
|-id=key-0-3
|3
|Calyculi of 4–8 bractlets (none longer than the 6–12 phyllaries); receptacles smooth
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Leaf margins thickened, minutely spinose (phyllaries 6–8); pappus bristles 10–15, plumose on distal 80%
|[[Stephanomeria parryi|Stephanomeria parryi]]
|-id=key-0-4
|4
|Leaf margins not thickened, not spinose (phyllaries 6–12); pappus bristles 25–40, wholly plumose
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Basal leaves runcinate, pinnately lobed; phyllaries 6–8; pappus bristles 30–40
|[[Stephanomeria thurberi|Stephanomeria thurberi]]
|-id=key-0-5
|5
|Basal leaves entire or sparsely toothed; phyllaries 8–12; pappus bristles 25—30
|[[Stephanomeria lactucina|Stephanomeria lactucina]]
|-id=key-0-6
|6
|Plants with woody caudices; pappus bristles tan or sordid, plumose on distal 80%
|[[Stephanomeria pauciflora|Stephanomeria pauciflora]]
|-id=key-0-6
|6
|Plants with rhizomes; pappus bristles white, wholly plumose
|[[#key-0-7| > 7]]
|-id=key-0-7
|7
|Cauline leaves present (green) at flowering (3–6 cm).
|[[Stephanomeria fluminea|Stephanomeria fluminea]]
|-id=key-0-7
|7
|Cauline leaves much reduced, bractlike at flowering
|[[#key-0-8| > 8]]
|-id=key-0-8
|8
|Plants 10–20(–25) cm; basal leaves runcinate, pinnately lobed
|[[Stephanomeria runcinata|Stephanomeria runcinata]]
|-id=key-0-8
|8
|Plants 20–70 cm; basal leaves entire or sparsely toothed.
|[[Stephanomeria tenuifolia|Stephanomeria tenuifolia]]
|-id=key-0-9
|9
|Cypselae without longitudinal groove on each face
|[[Stephanomeria virgata|Stephanomeria virgata]]
|-id=key-0-9
|9
|Cypselae with longitudinal groove on each face
|[[#key-0-10| > 10]]
|-id=key-0-10
|10
|Heads in paniculiform arrays; peduncles 10–40 mm
|[[Stephanomeria exigua|Stephanomeria exigua]]
|-id=key-0-10
|10
|Heads borne singly or clustered; peduncles 2–10 mm
|[[#key-0-11| > 11]]
|-id=key-0-11
|11
|Pappus bristles wholly plumose or at least to widened bases
|[[#key-0-12| > 12]]
|-id=key-0-11
|11
|Pappus bristles plumose on distal 50–85%, bases widened or not
|[[#key-0-13| > 13]]
|-id=key-0-12
|12
|Florets 5; calyculus bractlets appressed
|[[Stephanomeria paniculata|Stephanomeria paniculata]]
|-id=key-0-12
|12
|Florets 9–15; calyculus bractlets usually reflexed, rarely appressed
|[[Stephanomeria elata|Stephanomeria elata]]
|-id=key-0-13
|13
|Calyculus bractlets reflexed
|[[#key-0-14| > 14]]
|-id=key-0-13
|13
|Calyculus bractlets appressed
|[[#key-0-15| > 15]]
|-id=key-0-14
|14
|Florets 6–8; cypselae 5.5–6.8 mm; pappus bristles (persistent) plumose on distal 60–70%
|[[Stephanomeria exigua|Stephanomeria exigua]]
|-id=key-0-14
|14
|Florets 11–13; cypselae 1.9–2.3 mm; pappus bristles (falling) plumose on distal 80–85%
|[[Stephanomeria diegensis|Stephanomeria diegensis]]
|-id=key-0-15
|15
|Florets 5–11; cypselae 2.3–3.1 mm; pappus bristles plumose on distal 60–85%
|[[Stephanomeria exigua|Stephanomeria exigua]]
|-id=key-0-15
|15
|Florets 5–6; cypselae 3.3–3.8 mm; pappus bristles plumose on distal 50–60%
|[[Stephanomeria malheurensis|Stephanomeria malheurensis]]
|}
</div></div><!--

-->{{#Taxon:
name=Stephanomeria
|author=L. D. Gottlieb
|authority=Nuttall
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Asteraceae
|illustrator=Bee F. Gunn
|distribution=w North America;n Mexico.
|reference=gottlieb1971a;gottlieb1972a
|publication title=Trans. Amer. Philos. Soc., n. s.,
|publication year=1841
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse_grained_fna_xml/V19-20-21/V19_548.xml
|tribe=Asteraceae tribe Cichorieae
|genus=Stephanomeria
}}<!--

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