View source for Silphium

{{Treatment/ID
|accepted_name=Silphium
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=2: 919. 1753
|year=1753
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 391. 1754
|year=1754
}}
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Heliantheae;Asteraceae (tribe Heliantheae) subtribe Ecliptinae;Silphium
|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 Ecliptinae]]</div><div class="higher-taxon"><small>genus</small>[[Silphium]]</div></div>
|etymology=Greek silphion, an unknown plant appearing on ancient coins of the city of Cyrene
|volume=Volume 21
|mention_page=page 65, 157
|treatment_page=page 77
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Perennials,</b> 20–250+ cm (fibrous rooted, rhizomatous, or taprooted). <b>Stems</b> usually erect, usually branched (terete or square, often vernicose with resinous exudates). <b>Leaves</b> basal and cauline (basal persistent or withering before flowering); whorled, opposite, subopposite, or alternate (sometimes all conditions on one plant); petiolate or sessile; blades (1- or 3-nerved) deltate, elliptic, linear, ovate, or rhombic, sometimes 1–2-pinnately lobed or -pinnatifid, bases cordate or truncate to cuneate, margins entire or toothed, faces glabrous or hairy (sometimes stipitate-glandular). <b>Heads</b> radiate, in paniculiform or racemiform arrays. <b>Involucres</b> campanulate to hemispheric, 10–30 mm diam. <b>Phyllaries</b> persistent, 11–45 in 2–4 series (outer broader, foliaceous, inner smaller, thinner, each subtending a ray floret). <b>Receptacles</b> flat to slightly convex, paleate (paleae oblong, lanceolate, or linear). <b>Ray</b> florets 8–35+ in 1–4 series, pistillate, fertile; corollas yellow or white. <b>Disc</b> florets 20–200+, functionally staminate; corollas yellow or white, tubes much shorter than narrow, cylindric throats, lobes 5, deltate. <b>Cypselae</b> (black to brown) obflattened (± winged, shed alone without accessory structures); pappi 0, or persistent, of 2 awns (± confluent with cypsela shoulders and wings). <b>x</b> = 7.</span><!--

-->{{Treatment/Body
|distribution=North America.
|discussion=<p>Species 12 (12 in the flora).</p><!--
--><p>In keys and descriptions here, “plants scapiform” indicates plants with distal cauline leaves notably smaller than basal and proximal cauline leaves, and “plants caulescent” indicates plants with leaves ± uniform in size throughout; “leaves persistent” indicates leaves persisting to flowering time, and “leaves caducous” indicates leaves withering before flowering time.</p>
|tables=
|references={{Treatment/Reference
|id=perry1937a
|text=Perry, L. M. 1937. Notes on Silphium. Rhodora 39: 281–297.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Stems square (distal leaf or petiole bases connate-perfoliate)
|[[Silphium perfoliatum|Silphium perfoliatum]]
|-id=key-0-1
|1
|Stems terete or slightly 4-angled (distal leaves not perfoliate)
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Leaves (at least proximal) usually laciniate, pinnatifid, or 1–2-pinnately lobed (lobes 3–15)
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Leaves (proximal and distal) seldom lobed (sometimes with 2 basal lobes, then hastate, sagittate, or auriculate)
|[[#key-0-6| > 6]]
|-id=key-0-3
|3
|Ray florets 6–12
|[[Silphium compositum|Silphium compositum]]
|-id=key-0-3
|3
|Ray florets 14–40
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Corollas white
|[[Silphium albiflorum|Silphium albiflorum]]
|-id=key-0-4
|4
|Corollas yellow
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Phyllaries appressed, apices acute to obtuse
|[[Silphium terebinthinaceum|Silphium terebinthinaceum]]
|-id=key-0-5
|5
|Phyllaries reflexed or appressed, apices acuminate to caudate
|[[Silphium laciniatum|Silphium laciniatum]]
|-id=key-0-6
|6
|Plants taprooted (scapiform; cauline leaves notably smaller distally)
|[[#key-0-7| > 7]]
|-id=key-0-6
|6
|Plants fibrous rooted (caulescent; cauline leaves not notably smaller distally)
|[[#key-0-8| > 8]]
|-id=key-0-7
|7
|Ray flowers 6–12
|[[Silphium compositum|Silphium compositum]]
|-id=key-0-7
|7
|Ray flowers 17–29
|[[Silphium terebinthinaceum|Silphium terebinthinaceum]]
|-id=key-0-8
|8
|Leaves (at least proximal leaves) petiolate (never sessile), bases truncate, cordate, auriculate, hastate, or sagittate
|[[#key-0-9| > 9]]
|-id=key-0-8
|8
|Leaves (proximal and distal) petiolate (blade bases round to tapered) or sessile (blade bases round to cordate)
|[[#key-0-10| > 10]]
|-id=key-0-9
|9
|Stems glabrous; basal leaves caducous
|[[Silphium brachiatum|Silphium brachiatum]]
|-id=key-0-9
|9
|Stems hispid; basal leaves persistent
|[[Silphium wasiotense|Silphium wasiotense]]
|-id=key-0-10
|10
|Phyllaries: abaxial faces usually glabrous (rarely scabrous in outer series)
|[[#key-0-11| > 11]]
|-id=key-0-10
|10
|Phyllaries: abaxial faces glandular, hirsute, hispid, or scabrous
|[[#key-0-12| > 12]]
|-id=key-0-11
|11
|Ray florets 20–36+
|[[Silphium integrifolium|Silphium integrifolium]]
|-id=key-0-11
|11
|Ray florets 8–17
|[[Silphium asteriscus|Silphium asteriscus]]
|-id=key-0-12
|12
|Leaf faces stipitate-glandular
|[[Silphium glutinosum|Silphium glutinosum]]
|-id=key-0-12
|12
|Leaf faces eglandular
|[[#key-0-13| > 13]]
|-id=key-0-13
|13
|Basal leaves persistent
|[[#key-0-14| > 14]]
|-id=key-0-13
|13
|Basal leaves caducous
|[[#key-0-15| > 15]]
|-id=key-0-14
|14
|Leaf faces shaggy-hispid; phyllaries hispid; corollas pale yellow; cypselae 6–10mm; Alabama, Georgia, Tennessee
|[[Silphium mohrii|Silphium mohrii]]
|-id=key-0-14
|14
|Leaf faces hirsute, hispid, or scabrous; phyllaries scabrous; corollas bright yellow; cypselae 10–17 mm; Louisiana, Texas
|[[Silphium radula|Silphium radula]]
|-id=key-0-15
|15
|Cauline leaves opposite (clasping stems)
|[[Silphium integrifolium|Silphium integrifolium]]
|-id=key-0-15
|15
|Cauline leaves opposite or alternate (not clasping stems)
|[[#key-0-16| > 16]]
|-id=key-0-16
|16
|Ray florets 20–30+
|[[Silphium radula|Silphium radula]]
|-id=key-0-16
|16
|Ray florets 12–20
|[[Silphium asteriscus|Silphium asteriscus]]
|}
</div></div><!--

-->{{#Taxon:
name=Silphium
|author=Jennifer A. Clevinger
|authority=Linnaeus
|rank=genus
|parent rank=subtribe
|synonyms=
|basionyms=
|family=Asteraceae
|distribution=North America.
|reference=perry1937a
|publication title=Sp. Pl.;Gen. Pl. ed.
|publication year=1753;1754
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V19-20-21/V21_168.xml
|tribe=Asteraceae tribe Heliantheae
|subtribe=Asteraceae (tribe Heliantheae) subtribe Ecliptinae
|genus=Silphium
}}<!--

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