View source for Layia

{{Treatment/ID
|accepted_name=Layia
|accepted_authority=Hooker & Arnott ex de Candolle in A. P. de Candolle and A. L. P. P. de Candolle
|publications={{Treatment/Publication
|title=in A. P. de Candolle and A. L. P. P. de Candolle, Prodr.
|place=7: 294. 1838
|year=1838
}}
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Heliantheae;Asteraceae (tribe Heliantheae) subtribe Madiinae;Layia
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Heliantheae]]</div><div class="higher-taxon"><small>subtribe</small>[[Asteraceae (tribe Heliantheae) subtribe Madiinae]]</div><div class="higher-taxon"><small>genus</small>[[Layia]]</div></div>
|etymology=For George Tradescant Lay, a naturalist on Beechey’s voyage (1825–1828)
|volume=Volume 21
|mention_page=page 255, 259, 260, 263, 264
|treatment_page=page 262
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals,</b> 2–60(–130) cm. <b>Stems</b> usually ± erect (prostrate in L. chrysanthemoides and L. platyglossa of coastal bluffs). <b>Leaves</b> mostly cauline; proximal opposite, most alternate; sessile; blades ovate, lanceolate, or oblanceolate to linear, sometimes 1–2-pinnatifid, ultimate margins toothed or entire, faces glabrous or hirsute to strigose (distal leaves sometimes stipitate-glandular as well). <b>Heads</b> usually radiate (discoid in L. discoidea), borne singly or in ± corymbiform arrays. <b>Peduncular</b> bracts: pit-glands, tack-glands, and/or spines 0. <b>Involucres</b> ± hemispheric, campanulate, cylindric, ellipsoid, obconic, or urceolate, 2–15+ mm diam. <b>Phyllaries</b> 0 (then outer paleae functioning as phyllaries, in L. discoidea), or 3–27 in 1(–2) series (lanceolate to lance-attenuate or oblanceolate, herbaceous, each usually wholly enveloping a subtended ray ovary, abaxially hirsute to strigose or scabrous, sometimes glandular). <b>Receptacles</b> flat to convex, setulose, paleate (paleae falling, in 1 series, between rays and discs or subtending ± all disc florets, distinct, phyllary-like, more scarious). <b>Ray</b> florets 0 or 3–27, pistillate, fertile; corollas yellow, cream, white, or bicolored. <b>Disc</b> florets 5–120+, bisexual, fertile; corollas yellow, tubes shorter than funnelform throats, lobes 5, deltate (anthers ± dark purple or yellow to brownish; styles glabrous proximal to branches). <b>Ray</b> cypselae obcompressed, clavate (± arcuate to falcate, basal attachments central, apices beakless, faces glabrous or sparsely hairy); pappi 0. <b>Disc</b> cypselae ± clavate (usually ± strigose to sericeous, sometimes glabrous); pappi 0 or of 1–32 elliptic, lance-attenuate, ovate, setiform, or subulate, glabrous, scabrous, or plumose scales or bristles (often each basally villous and/or adaxially woolly). <b>x</b> = 8.</span><!--

-->{{Treatment/Body
|distribution=w North America;nw Mexico.
|discussion=<p>Species 14 (14 in the flora).</p><!--
--><p>Layia is evidently most closely related to Lagophylla based on molecular phylogenetic data. Species of Layia with 2n = 14 constitute a clade that has been regarded as exemplary of geographic diversification (speciation) in plants (J. Clausen 1951; B. G. Baldwin, unpubl.). All members of Layia except L. carnosa and L. hieracioides are self-incompatible.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Disc pappi 0
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Disc pappi of 1–32 bristles or scales
|[[#key-0-7| > 7]]
|-id=key-0-2
|2
|Plants not glandular; paleae subtending ± all disc florets
|[[Layia chrysanthemoides|Layia chrysanthemoides]]
|-id=key-0-2
|2
|Plants glandular; paleae in 1 (involucre-like) series between ray and disc florets
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Plants apple- or banana-scented; margins (basal leaves) usually denticulate to serrulate, seldom lobed; ray corollas white to cream
|[[Layia heterotricha|Layia heterotricha]]
|-id=key-0-3
|3
|Plants unscented, or not apple- or banana-scented; margins (basal leaves) lobed; ray corollas white, yellow, or bicolored (proximally yellow, distally whitish)
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Stems usually purple-streaked; involucres campanulate to hemispheric, subglobose, or ± urceolate
|[[#key-0-5| > 5]]
|-id=key-0-4
|4
|Stems usually not purple-streaked; involucres ± hemispheric
|[[#key-0-6| > 6]]
|-id=key-0-5
|5
|Involucres campanulate to hemispheric or subglobose; ray florets 6–18, corollas yellow or bicolored (proximally yellow, distally whitish)
|[[Layia gaillardioides|Layia gaillardioides]]
|-id=key-0-5
|5
|Involucres ± urceolate; ray florets 13–27 (in 2 series), corollas bicolored
|[[Layia jonesii|Layia jonesii]]
|-id=key-0-6
|6
|Plants strongly lemon- or acrid-scented; ray corollas white or yellow; anthersyellow or brownish
|[[Layia pentachaeta|Layia pentachaeta]]
|-id=key-0-6
|6
|Plants not strongly scented; ray corollas yellow or bicolored (proximally yellow, distally white); anthers ± dark purple (sometimes yellow to brownish in sw California)
|[[Layia platyglossa|Layia platyglossa]]
|-id=key-0-7
|7
|Ray florets 0
|[[Layia discoidea|Layia discoidea]]
|-id=key-0-7
|7
|Ray florets 3–27 (ray laminae sometimes inconspicuous)
|[[#key-0-8| > 8]]
|-id=key-0-8
|8
|Plants not glandular; paleae subtending ± all disc florets
|[[#key-0-9| > 9]]
|-id=key-0-8
|8
|Plants glandular; paleae in 1 (involucre-like) series between ray and disc florets
|[[#key-0-10| > 10]]
|-id=key-0-9
|9
|Disc pappi of unequal, subulate to setiform scales
|[[Layia chrysanthemoides|Layia chrysanthemoides]]
|-id=key-0-9
|9
|Disc pappi of ± equal, lance-attenuate scales
|[[Layia fremontii|Layia fremontii]]
|-id=key-0-10
|10
|Disc pappi of elliptic, lance-linear, or ovate, non-plumose, non-woolly scales (bases sparsely setose), 0.5–3.5 mm
|[[#key-0-11| > 11]]
|-id=key-0-10
|10
|Disc pappi usually of bristles or setiform scales, if scales linear-attenuate to subulate, then proximally plumose and often proximally woolly adaxially, 1–7 mm
|[[#key-0-13| > 13]]
|-id=key-0-11
|11
|Ray corollas white; anthers yellow to brownish; ray cypselae sparsely hairy
|[[Layia leucopappa|Layia leucopappa]]
|-id=key-0-11
|11
|Ray corollas yellow or bicolored (proximally yellow, distally white); anthers ± dark purple; ray cypselae glabrous or sparsely hairy
|[[#key-0-12| > 12]]
|-id=key-0-12
|12
|Stems usually purple-streaked; involucres ± urceolate; ray florets 13–27 (in 2 series); ray cypselae glabrous; pappus scales 0.5–2 mm
|[[Layia jonesii|Layia jonesii]]
|-id=key-0-12
|12
|Stems not purple-streaked; involucres hemispheric to ± urceolate; ray florets 6–15; ray cypselae glabrous or sparsely hairy; pappusscales 2–3.5 mm
|[[Layia munzii|Layia munzii]]
|-id=key-0-13
|13
|Plants usually not strongly scented (if not contacted); disc pappus bristles or scales mostly proximally plumose and adaxially woolly, sometimes ± scabrous throughout, if proximally plumose and not woolly, then linear-attenuate to subulate scales
|[[#key-0-14| > 14]]
|-id=key-0-13
|13
|Plants usually strongly scented, even without contact (except L. carnosa, fleshy-leaved plants of coastal dunes); disc pappus bristles or scales proximally plumose, seldom woolly adaxially (not linear-attenuate to subulate)
|[[#key-0-16| > 16]]
|-id=key-0-14
|14
|Ray corollas usually white (sometimes yellow); disc pappi of 10–15 linearattenuate to subulate scales
|[[Layia glandulosa|Layia glandulosa]]
|-id=key-0-14
|14
|Ray corollas yellow or bicolored (proximally yellow, distally white); disc pappi of 14–32 bristles or setiform scales
|[[#key-0-15| > 15]]
|-id=key-0-15
|15
|Involucres usually ± hemispheric; phyllary apices often longer than folded bases; ray corollas yellow or bicolored (proximally yellow, distally white); anthers usually ± dark purple (sometimes yellow to brownish in sw California); disc pappus bristles or scales usually scabrous (sometimes proximally plumose and adaxially woolly in sw California)
|[[Layia platyglossa|Layia platyglossa]]
|-id=key-0-15
|15
|Involucres ± ellipsoid to campanulate; phyllary apices usually shorter than folded bases; ray corollas yellow; anthers yellow to brownish; disc pappus bristles orscales proximally plumose and adaxially woolly
|[[Layia septentrionalis|Layia septentrionalis]]
|-id=key-0-16
|16
|Margins (basal leaves) usually denticulate or serrulate, seldom toothed or lobed;ray corollas white to cream (disc pappi readily falling as units)
|[[Layia heterotricha|Layia heterotricha]]
|-id=key-0-16
|16
|Margins (basal leaves) lobed; ray corollas white, yellow, or bicolored (proximally yellow, distally whitish)
|[[#key-0-17| > 17]]
|-id=key-0-17
|17
|Anthers yellow to brownish
|[[Layia pentachaeta|Layia pentachaeta]]
|-id=key-0-17
|17
|Anthers ± dark purple
|[[#key-0-18| > 18]]
|-id=key-0-18
|18
|Stems not purple-streaked; ray corollas white, laminae 1.5–3.5 mm; ray cypselae sparsely hairy
|[[Layia carnosa|Layia carnosa]]
|-id=key-0-18
|18
|Stems purple-streaked; ray corollas yellow or bicolored (proximally yellow, distally white), laminae 1–18 mm; ray cypselae glabrous
|[[#key-0-19| > 19]]
|-id=key-0-19
|19
|Ray corollas yellow or bicolored (proximally yellow, distally whitish), 3.5–18 mm; disc pappi of 15–24 bristles or setiform scales (main stemsascending, not strictly erect)
|[[Layia gaillardioides|Layia gaillardioides]]
|-id=key-0-19
|19
|Ray corollas yellow, 1–4 mm; disc pappi of 10–16 bristles or setiform scales (main stems strictly erect)
|[[Layia hieracioides|Layia hieracioides]]
|}
</div></div><!--

-->{{#Taxon:
name=Layia
|author=Bruce G. Baldwin;Susan J. Bainbridge;John L. Strother
|authority=Hooker & Arnott ex de Candolle in A. P. de Candolle and A. L. P. P. de Candolle
|rank=genus
|parent rank=subtribe
|synonyms=
|basionyms=
|family=Asteraceae
|distribution=w North America;nw Mexico.
|reference=None
|publication title=in A. P. de Candolle and A. L. P. P. de Candolle, Prodr.
|publication year=1838
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/9216fc802291cd3df363fd52122300479582ede7/coarse_grained_fna_xml/V19-20-21/V21_644.xml
|tribe=Asteraceae tribe Heliantheae
|subtribe=Asteraceae (tribe Heliantheae) subtribe Madiinae
|genus=Layia
}}<!--

-->[[Category:Treatment]][[Category:Asteraceae (tribe Heliantheae) subtribe Madiinae]]