View source for Ageratina

{{Treatment/ID
|accepted_name=Ageratina
|accepted_authority=Spach
|publications={{Treatment/Publication
|title=Hist. Nat. Vég.
|place=10: 286. 1841
|year=1841
}}
|common_names=Snakeroot
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Eupatorieae;Ageratina
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Eupatorieae]]</div><div class="higher-taxon"><small>genus</small>[[Ageratina]]</div></div>
|etymology=Generic name Ageratum and Latin - ina, diminutive
|volume=Volume 21
|mention_page=page 461, 462, 541, 552
|treatment_page=page 547
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="whole-organism duration;whole_organism some measurement;whole_organism growth form;whole_organism growth form"><b>Perennials,</b> subshrubs, or shrubs [trees], mostly 20–220 cm.</span> <span class="statement" id="st-d0_s1" data-properties="stem orientation;stem growth form;stem architecture"><b>Stems </b>usually erect, rarely scandent, sparsely to densely branched.</span> <span class="statement" id="st-d0_s2" data-properties=""><b>Leaves </b>cauline;</span> <span class="statement" id="st-d0_s3" data-properties="">mostly opposite (distal sometimes alternate);</span> <span class="statement" id="st-d0_s4" data-properties="leaf position;leaf arrangement;leaf architecture">petiolate;</span> <span class="statement" id="st-d0_s5" data-properties="blade architecture;blade shape;blade shape;blade shape;blade shape;blade shape;blade shape;blade shape;blade shape;margin architecture or shape;margin shape;margin architecture or shape;margin architecture or shape;margin architecture or shape;margin architecture or shape;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence">blades 3 (–5) -nerved from bases, usually deltate, lanceolate, ovate, rhombic, or triangular, sometimes orbiculate, margins entire, crenate, dentate, or serrate, faces glabrous or hispidulous, pilose, or puberulent, sometimes glanddotted (A. occidentalis, A. adenophora).</span> <span class="statement" id="st-d0_s6" data-properties="head architecture or shape;head arrangement;array architecture or arrangement;array architecture"><b>Heads </b>discoid, usually in compact, (terminal and axillary) corymbiform arrays, sometimes borne singly.</span> <span class="statement" id="st-d0_s7" data-properties="involucre shape;involucre diameter"><b>Involucres </b>campanulate, 3–6 mm diam.</span> <span class="statement" id="st-d0_s8" data-properties="phyllary duration;phyllary quantity;phyllary architecture;phyllary architecture;phyllary shape;phyllary variability;series atypical quantity;series quantity"><b>Phyllaries </b>persistent, 8–30 in 2 (–3) series, 0-nerved or 2-nerved, lanceolate to linear, ± equal (herbaceous).</span> <span class="statement" id="st-d0_s9" data-properties="floret quantity"><b>Florets </b>10–60;</span> <span class="statement" id="st-d0_s10" data-properties="corolla coloration;corolla coloration;throat shape">corollas white or lavender, throats obconic to campanulate (lengths 1.5–2 times diams.);</span> <span class="statement" id="st-d0_s11" data-properties="base size;base pubescence;branch arrangement or course or shape;branch shape">styles: bases sometimes enlarged, glabrous, branches linear, seldom distally dilated.</span> <span class="statement" id="st-d0_s12" data-properties="receptacle shape;receptacle architecture"><b>Receptacles </b>convex (glabrous or hairy), epaleate.</span> <span class="statement" id="st-d0_s13" data-properties="cypsela shape;cypsela shape;cypsela architecture or shape;cypsela relief"><b>Cypselae </b>prismatic or ± fusiform, usually 5-ribbed, scabrellous and/or glanddotted;</span> <span class="statement" id="st-d0_s14" data-properties="bristle quantity;bristle architecture;series quantity">pappi usually persistent, sometimes fragile, rarely falling, of 5–40, barbellulate bristles in 1 series.</span> <span class="statement" id="st-d0_s15" data-properties="pappus duration;pappus fragility;pappus life cycle;x chromosome quantity">x = 17.</span><!--

-->{{Treatment/Body
|distribution=North America;Mexico;Central America;Andean South America
|discussion=<p>Species ca. 250 (14 in the flora).</p>
|tables=
|references={{Treatment/Reference
|id=clewell1971a
|text=Clewell, A. F. and J. W. Wooten. 1971. A revision of Ageratina (Compositae: Eupatorieae) from eastern North America. Brittonia 23: 123–143
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Shrubs
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Perennials or subshrubs
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Petioles (2–)3–5 mm; leaf blades 1–2 cm, margins entire or shallowly crenate, facesgland-dotted
|[[Ageratina wrightii|Ageratina wrightii]]
|-id=key-0-2
|2
|Petioles 3–10(–15) mm; leaf blades (2–)3–5(–7) cm, margins coarsely crenate, facesnot gland-dotted
|[[Ageratina havanensis|Ageratina havanensis]]
|-id=key-0-3
|3
|Leaves alternate on at least distal 1/4–1/2 of stems
|[[#key-0-4| > 4]]
|-id=key-0-3
|3
|Leaves opposite
|[[#key-0-6| > 6]]
|-id=key-0-4
|4
|Heads usually borne singly (rarely 2s or 3s); involucres 11–12 mm
|[[Ageratina shastensis|Ageratina shastensis]]
|-id=key-0-4
|4
|Heads usually 5–10 (axillary clusters usually forming elongate or broad aggregates); involucres 2.5–3.5(–4) mm
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Leaves alternate on distal 1/4–1/2 of stems; involucres 3–3.5(–4) mm; corollas pink, bluish, or white tinged with purple (not orange-veined); cypselae sessile-glandular
|[[Ageratina occidentalis|Ageratina occidentalis]]
|-id=key-0-5
|5
|Leaves alternate (from bases to apices of stems); involucres 2.5–3 mm; corollaswhite (prominently orange-veined); cypselae eglandular
|[[Ageratina thyrsiflora|Ageratina thyrsiflora]]
|-id=key-0-6
|6
|Peduncles densely stipitate-glandular
|[[Ageratina adenophora|Ageratina adenophora]]
|-id=key-0-6
|6
|Peduncles puberulent, glabrous, or glabrescent (not glandular)
|[[#key-0-7| > 7]]
|-id=key-0-7
|7
|Flowering in spring; leaves usually narrowly lanceolate, 0.5–1.5 cm wide,apically long-acuminate; involucres 2.5–3 mm; cypselae glabrous
|[[Ageratina paupercula|Ageratina paupercula]]
|-id=key-0-7
|7
|Flowering in fall; leaves ovate to lanceolate-ovate, triangular, or lanceolate, (0.5–)1.5–9 cm wide, apically acute to acuminate; involucres (in A. jucunda 2.5–)3.5–7 mm; cypselae usually hairy (glabrous in A. altissima)
|[[#key-0-8| > 8]]
|-id=key-0-8
|8
|Leaves mostly sessile; heads in open, loose arrays, peduncles 10–60 mm
|[[Ageratina lemmonii|Ageratina lemmonii]]
|-id=key-0-8
|8
|Leaves distinctly petiolate; heads in compact clusters, ultimate peduncles 1–15(–20) mm
|[[#key-0-9| > 9]]
|-id=key-0-9
|9
|Petioles 1–22 mm (distal leaves greatly reduced in size well proximal to heads); leaf blades 2–7(–9) × 1.5–4 cm (relatively thick)
|[[#key-0-10| > 10]]
|-id=key-0-9
|9
|Petioles (5–)10–70 or 2–20 (in A. rothrockii) mm; leaf blades 2–11(–13) × 1.5–9 cm (relatively thin)
|[[#key-0-11| > 11]]
|-id=key-0-10
|10
|Petioles 1–8(–12) mm; leaf margins crenate or less commonlycrenate-serrate to dentate or subentire
|[[Ageratina aromatica|Ageratina aromatica]]
|-id=key-0-10
|10
|Petioles 7–15(–22) mm; leaf margins coarsely serrate or incised orless commonly crenate to subentire
|[[Ageratina jucunda|Ageratina jucunda]]
|-id=key-0-11
|11
|Leaves (yellow-green or grayish yellow-green): blades triangular to lanceolate-ovate or ovate, 2–5(–7) × 1.5–3.5(–4.5) cm; phyllariesusually granular-puberulent
|[[Ageratina herbacea|Ageratina herbacea]]
|-id=key-0-11
|11
|Leaves (green, rarely yellowish): blades lanceolate to lanceolate-ovate, 4–11(–13) × 2.5–9 cm; phyllaries glabrous, villous, or villous-puberulent
|[[#key-0-12| > 12]]
|-id=key-0-12
|12
|Stems glabrous; leaf blades broadly deltate-ovate (thin, delicate), apices obtuse; corolla lobes glabrous or sparselypuberulent
|[[Ageratina luciae-brauniae|Ageratina luciae-brauniae]]
|-id=key-0-12
|12
|Stems puberulent; leaf blades deltate-ovate to ovate or broadly lanceolate, apices acute to acuminate; corolla lobes short-villous
|[[#key-0-13| > 13]]
|-id=key-0-13
|13
|Peduncles 1–5 mm; involucres 4–5 mm; cypselae glabrous;e United States and Canada
|[[Ageratina altissima|Ageratina altissima]]
|-id=key-0-13
|13
|Peduncles 5–12(–20) mm; involucres 5–7 mm; cypselae sparsely and finely strigose-hirsute; Arizona, New Mexico, sw Texas
|[[Ageratina rothrockii|Ageratina rothrockii]]
|}
</div></div><!--

-->{{#Taxon:
name=Ageratina
|author=Guy L. Nesom
|authority=Spach
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Asteraceae
|distribution=North America;Mexico;Central America;Andean South America
|reference=clewell1971a
|publication title=Hist. Nat. Vég.
|publication year=1841
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V19-20-21/V21_1389.xml
|tribe=Asteraceae tribe Eupatorieae
|genus=Ageratina
|array architecture=corymbiform
|array architecture or arrangement=compact
|base pubescence=glabrous
|base size=enlarged
|blade architecture=3(-5)-nerved
|blade shape=orbiculate;triangular;rhombic;triangular;rhombic;ovate;lanceolate;deltate
|branch arrangement or course or shape=linear
|branch shape=dilated
|bristle architecture=barbellulate
|bristle quantity=5;40
|corolla coloration=lavender;white
|cypsela architecture or shape=5-ribbed
|cypsela relief=scabrellous
|cypsela shape=fusiform;prismatic
|face pubescence=puberulent;pilose;hispidulous;glabrous;puberulent;pilose;hispidulous;glabrous;puberulent;pilose;hispidulous;glabrous
|floret quantity=10;60
|head architecture or shape=discoid
|head arrangement=singly
|involucre diameter=3mm;6mm
|involucre shape=campanulate
|leaf architecture=petiolate
|leaf arrangement=opposite
|leaf position=cauline
|margin architecture or shape=serrate;dentate;serrate;dentate;entire
|margin shape=crenate
|pappus duration=persistent
|pappus fragility=fragile
|pappus life cycle=falling
|phyllary architecture=2-nerved;0-nerved
|phyllary duration=persistent
|phyllary quantity=8;30
|phyllary shape=lanceolate;linear
|phyllary variability=equal
|receptacle architecture=epaleate
|receptacle shape=convex
|series atypical quantity=2;3
|series quantity=1;2
|stem architecture=branched
|stem growth form=scandent
|stem orientation=erect
|throat shape=obconic;campanulate
|whole-organism duration=perennial
|whole_organism growth form=shrub;subshrub
|whole_organism some measurement=20cm;220cm
|x chromosome quantity=17
}}<!--

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