View source for Thalictrum

{{Treatment/ID
|accepted_name=Thalictrum
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=1: 545. 175
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 242. 1754
|year=1754
}}
|common_names=Meadow-rue;pigamon
|basionyms=
|synonyms=
|hierarchy=Ranunculaceae;Thalictrum
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Ranunculaceae]]</div><div class="higher-taxon"><small>genus</small>[[Thalictrum]]</div></div>
|etymology=Thaliktron, an ancient name used by Dioscorides
|volume=Volume 3
|mention_page=page 258
|treatment_page=
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="whole_organism duration;whole_organism growth form;rhizome texture;caudex texture;root architecture"><b>Herbs,</b> perennial, from woody rhizomes, caudices, or tuberous roots.</span> <span class="statement" id="st-d0_s1" data-properties="leaf position;leaf position;proximal leaf architecture;distal leaf architecture"><b>Leaves </b>basal and cauline, proximal leaves petiolate, distal leaves sessile;</span> <span class="statement" id="st-d0_s2" data-properties="cauline leaf arrangement">cauline leaves alternate.</span> <span class="statement" id="st-d0_s3" data-properties="leaf-blade architecture"><b>Leaf-</b>blade 1-4×-ternately or pinnately compound;</span> <span class="statement" id="st-d0_s4" data-properties="leaflet shape;leaflet shape;leaflet shape;leaflet shape;leaflet shape;leaflet shape;leaflet shape;margin shape;margin shape">leaflets cordate-reniform, obovate, lanceolate, or linear, sometimes 3-lobed or more, margins entire or crenate.</span> <span class="statement" id="st-d0_s5" data-properties="inflorescence position or structure subtype;inflorescence position;panicle architecture;flower architecture or arrangement or growth form;flower some measurement"><b>Inflorescences </b>terminal, sometimes also axillary, (1-) 2-200-flowered panicles, racemes, corymbs, umbels, or flowers solitary, to 41 cm;</span> <span class="statement" id="st-d0_s6" data-properties="involucre presence;involucre presence;involucral-bract quantity;involucral-bract architecture or shape">involucres absent or present, involucral-bracts 2-3 (these compound, often resembling whorl of 6-9 simple bracts), leaflike, not closely subtending flowers.</span> <span class="statement" id="st-d0_s7" data-properties="flower reproduction;flower reproduction;flower reproduction;flower sexes;flower architecture or shape"><b>Flowers </b>all bisexual, bisexual and unisexual on same plant, or all unisexual with sexes on same or different plants, radially symmetric;</span> <span class="statement" id="st-d0_s8" data-properties="sepal duration;sepal coloration;sepal shape;sepal shape;sepal some measurement;fruit quantity">sepals not persistent in fruit, 4-10, whitish to greenish yellow or purplish, plane, lanceolate to reniform or spatulate, 1-18 mm;</span> <span class="statement" id="st-d0_s9" data-properties="petal presence">petals absent;</span> <span class="statement" id="st-d0_s10" data-properties="stamen quantity">stamens 7-30;</span> <span class="statement" id="st-d0_s11" data-properties="filament shape">filaments filiform to clavate or distally dilated;</span> <span class="statement" id="st-d0_s12" data-properties="staminode presence">staminodes absent between stamens and pistils;</span> <span class="statement" id="st-d0_s13" data-properties="pistil quantity;pistil architecture">pistils 1-16, simple;</span> <span class="statement" id="st-d0_s14" data-properties="ovule quantity">ovule 1 per pistil;</span> <span class="statement" id="st-d0_s15" data-properties="style presence;style presence">style present or absent.</span> <span class="statement" id="st-d0_s16" data-properties="fruits achene architecture;fruits achene architecture;fruits achene architecture;fruits achene shape;fruits achene shape;fruits achene architecture or shape;side architecture;side architecture"><b>Fruits </b>achenes, usually aggregate, sessile or stipitate, ovoid to obovoid, falcate, or discoid, sides prominently veined or ribbed;</span> <span class="statement" id="st-d0_s17" data-properties="beak presence;beak presence;beak position or structure subtype;beak course;beak architecture;beak some measurement;x chromosome quantity">beak present or absent, terminal, straight to coiled, 0-4 mm. <b>x</b> = 7.</span><!--

-->{{Treatment/Body
|distribution=Nearly worldwide;mostly temperate
|discussion=<p>Species 120-200 (22 in the flora).</p><!--
--><p>Thalictrum is a taxonomically difficult genus that should be carefully researched through additional population-based field studies. Past treatments of Thalictrum have often emphasized leaf characters that are highly variable in most species; they are therefore of poor diagnostic value and not indicati relationships. Because of the paucity of field studies and a continuing emphasis on highly variable characters, the literature is replete with names that do not represent distinct entities. Often mixes of character states can be found within a single population; many of the character states used in past studies were neither ecologically nor geographically distinct.</p><!--
--><p>Some species of Thalictrum have been divided into varieties by previous authors. In the absence of carefully collected, supporting evidence from field studies, we are unwilling to perpetuate the use of any infraspecific names.</p><!--
--><p>Characters useful in identifying species of Thalictrum include leaflet shape, degree of dilation of filaments, anther length, shape of anther apex, achene shape and venation patterns, and vestiture (glands and/or hairs) of leaves and achenes. Leaflets described in this treatment are the central, distalmost of a midstem leaf; proximal and distal leaves are more variable and often not representative of the species. Stigma and filament colors refer to fresh material in the following descriptions.</p><!--
--><p>In Thalictrum species, the stigma extends down the side of the style, so length of style in fruit (beak) includes the stigma.</p><!--
--><p>For many species no reliable characteristics for the identification of staminate material are known. Extensive field work and careful analysis are required to determine if such characteristics exist.</p><!--
--><p>In a narrow strip from southeastern Ontario to Ohio to Louisiana, some individuals of some species in Thalictrum section Leucocoma may lack their normal vestiture. In the absence of glands or pubescence, the differences among species are difficult to describe. The remaining characteristics overlap considerably. The species involved may be identified in the final couplets of the key as follows: if the plant in hand falls into the area of overlap for the first character of the couplet, go on to the next character, and so forth, until a distinguishing character is found. One or more of the characters offered should distinguish the infrequent, problematic individual.</p><!--
--><p>Several species of Thalictrum are used as ornamentals. At least one species, T. aquilegiifolium Linnaeus, occasionally escapes cultivation in Ontario and Quebec and possibly elsewhere. The plant is tall (40-100 cm); flowers bisexual, mauve to pink; and achenes few, filiform, 3-winged, stipitate, very small, and hidden at anthesis among the bases of long, rigid stamens.</p><!--
--><p>Numerous alkaloids have been identified from plants of the genus, some with pharmacologic potential. Some exhibit antimicrobial activity; others inhibit growth of tumors or lower blood pressure in mammals.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Inflorescences umbels or flowers solitary (sect. Anemonella).
|[[Thalictrum thalictroides|Thalictrum thalictroides]]
|-id=key-0-1
|1
|Inflorescences panicles, racemes, or corymbs.
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Flowers bisexual; sepals 5 (often 4 in T. alpinum).
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Flowers unisexual, or unisexual and bisexual, rarely only bisexual; sepals 4(–6).
|[[#key-0-7| > 7]]
|-id=key-0-3
|3
|Achenes sessile to nearly sessile; filaments filiform (sect. Thalictrum).
|[[#key-0-4| > 4]]
|-id=key-0-3
|3
|Achenes stipitate; filaments ± dilated distally.
|[[#key-0-5| > 5]]
|-id=key-0-4
|4
|Stems 15–150 cm; sepals 3–4mm; achenes 3–15.
|[[Thalictrum minus|Thalictrum minus]]
|-id=key-0-4
|4
|Stems (3–)5–20(–30) cm; sepals 1–2.3(–2.7) mm; achenes 2–6.
|[[Thalictrum alpinum|Thalictrum alpinum]]
|-id=key-0-5
|5
|Filaments weakly dilated; achenes short-stipitate, stipe less than 1.5 mm, body (4–)5–6 m; Canada, w United States (sect. Omalophysa).
|[[Thalictrum sparsiflorum|Thalictrum sparsiflorum]]
|-id=key-0-5
|5
|Filaments strongly clavate; achenes long-stipitate, stipe 1–3.5(–4) mm, body 2.5–5 mm; se United States (sect. Physocarpum).
|[[#key-0-6| > 6]]
|-id=key-0-6
|6
|Adaxial margin of achene concave, ca. 2 times length of stipe; filaments 2.5–4 mm.
|[[Thalictrum clavatum|Thalictrum clavatum]]
|-id=key-0-6
|6
|Adaxial margin of achene straight, ± equaling length of stipe; filaments 2–3 mm
|[[Thalictrum mirabile|Thalictrum mirabile]]
|-id=key-0-7
|7
|Leaflets apically 3–12-lobed, lobe margins crenate (rarely entire in T. debile); filaments variously colored, rarely white, filiform (sect. Heterogamia).
|[[#key-0-8| > 8]]
|-id=key-0-7
|7
|Leaflets undivided or 3-lobed apically, lobe margins entire (some leaflet margins on some individuals rarely crenate); filaments usually white, rarely lavender, filiform to clavate (sect. Leucocoma).
|[[#key-0-18| > 18]]
|-id=key-0-8
|8
|Lateral veins of achene anastomosing-reticulate.
|[[Thalictrum polycarpum|Thalictrum polycarpum]]
|-id=key-0-8
|8
|Lateral veins of achene not reticulate, veins parallel, converging, or rarely branched.
|[[#key-0-9| > 9]]
|-id=key-0-9
|9
|Achenes laterally compressed.
|[[#key-0-10| > 10]]
|-id=key-0-9
|9
|Achenes not laterally compressed, or very slightly so.
|[[#key-0-11| > 11]]
|-id=key-0-10
|10
|Leaf blade membranous, green; leaflets (5–)10–20 × (6–)8– 12(–18) mm; stems (20–)30–60(–150) cm; achenes 7–11(–14) per flower.
|[[Thalictrum fendleri|Thalictrum fendleri]]
|-id=key-0-10
|10
|Leaf blade leathery, glaucous; leaflets 5–8 × 4–5 mm; stems 14–50 cm; achenes 4–5(–6) per flower.
|[[Thalictrum heliophilum|Thalictrum heliophilum]]
|-id=key-0-11
|11
|Achenes stipitate; stipe 0.7–2.5 mm.
|[[#key-0-12| > 12]]
|-id=key-0-11
|11
|Achenes nearly sessile; stipe 0–0.3 mm.
|[[#key-0-13| > 13]]
|-id=key-0-12
|12
|Achenes erect; beak 1.5–3 mm.
|[[Thalictrum coriaceum|Thalictrum coriaceum]]
|-id=key-0-12
|12
|Achenes spreading to reflexed; beak 3–4.5(–6) mm.
|[[Thalictrum occidentale|Thalictrum occidentale]]
|-id=key-0-13
|13
|Achenes incurved.
|[[#key-0-14| > 14]]
|-id=key-0-13
|13
|Achenes straight.
|[[#key-0-15| > 15]]
|-id=key-0-14
|14
|Beak (2–)2.5–4(–5) mm; adaxial surface of achene 4–6 mm.
|[[Thalictrum confine|Thalictrum confine]]
|-id=key-0-14
|14
|Beak 1.5–2.5(–3) mm; adaxial surface of achene 3– 4(–6) mm.
|[[Thalictrum venulosum|Thalictrum venulosum]]
|-id=key-0-15
|15
|Roots fibrous; stems erect, 30–80 cm; largest leaflets more than 15 mm wide.
|[[Thalictrum dioicum|Thalictrum dioicum]]
|-id=key-0-15
|15
|Roots tuberous; stems reclining to erect, usually less than 30(–45) cm; largest leaflets less than 15 mm wide.
|[[#key-0-16| > 16]]
|-id=key-0-16
|16
|Beak 0.5–1 mm; achenes ovoid; stems erect; roots black when dry.
|[[Thalictrum texanum|Thalictrum texanum]]
|-id=key-0-16
|16
|Beak 1.3–2mm; achenes oblong to elliptic-lanceolate; stems reclining or decumbent; roots brown.
|[[#key-0-17| > 17]]
|-id=key-0-17
|17
|Achenes 0.7–1.2 mm wide, veins 6–8, prominent; beak 1.3–3 mm.
|[[Thalictrum debile|Thalictrum debile]]
|-id=key-0-17
|17
|Achenes 1.5–2 mm wide, veins 10–12; beak (1.3–)2.3–3 mm.
|[[Thalictrum arkansanum|Thalictrum arkansanum]]
|-id=key-0-18
|18
|Achenes, peduncles, abaxial surfaces of leaflets, and/or petioles and rachises with stipitate glands.
|[[Thalictrum amphibolum|Thalictrum amphibolum]]
|-id=key-0-18
|18
|Achenes, peduncles, abaxial surfaces of leaflets, and/or petioles and rachises without stipitate glands.
|[[#key-0-19| > 19]]
|-id=key-0-19
|19
|Achenes, peduncles, abaxial surfaces of leaflets, and/or petioles and rachises with minute papillae (i.e., sessile glands), may also be pubescent.
|[[#key-0-20| > 20]]
|-id=key-0-19
|19
|Achenes, peduncles, abaxial surfaces of leaflets, petioles, and rachises without papillae, may be pubescent or glabrous.
|[[#key-0-21| > 21]]
|-id=key-0-20
|20
|Leaflet length 0.9–5.25 times width; nonglandular trichomes absent; filaments 2.5–7.8 mm; anthers (0.7–)1.2–2.7(–3) mm; stipe 0.2–1.7 mm; e North America, rare w of Missouri.
|[[Thalictrum amphibolum|Thalictrum amphibolum]]
|-id=key-0-20
|20
|Leaflet length 0.9–2.6 times width; nonglandular trichomes present or absent; filaments 2–6.5 mm; anthers 1–3.6(–4) mm; stipe 0–1.1 mm; c North America, very rare e of Ohio.
|[[Thalictrum dasycarpum|Thalictrum dasycarpum]]
|-id=key-0-21
|21
|Achenes, peduncles, abaxial surfaces of leaflets, and/or petioles and rachises pubescent.
|[[#key-0-22| > 22]]
|-id=key-0-21
|21
|Achenes, peduncles, abaxial surfaces of leaflets, and/or petioles and rachises glabrous.
|[[#key-0-23| > 23]]
|-id=key-0-22
|22
|Anthers less than 1.5 mm, apex blunt or slightly apiculate; filaments rigid, ascending, prominently clavate; beak straight or coiled distally, ca. 1/2 as long as achene body.
|[[Thalictrum pubescens|Thalictrum pubescens]]
|-id=key-0-22
|22
|Anthers usually 1–3.6(–4) mm, apex usually strongly apiculate; filaments flexible, drooping, filiform, scarcely dilated distally; beak ± straight, filiform, about as long as achene body.
|[[Thalictrum dasycarpum|Thalictrum dasycarpum]]
|-id=key-0-23
|23
|Leaflets linear to narrowly lanceolate or oblanceolate, (2.6–)4–26 times longer than wide.
|[[Thalictrum cooleyi|Thalictrum cooleyi]]
|-id=key-0-23
|23
|Leaflets nearly orbiculate to ovate, or lanceolate to obovate, usually less than 4 times longer than wide.
|[[#key-0-24| > 24]]
|-id=key-0-24
|24
|Leaflets undivided or apically 2–3-lobed, largest usually less than 22 mm wide; filaments 1.8–4 mm; se United States.
|[[Thalictrum macrostylum|Thalictrum macrostylum]]
|-id=key-0-24
|24
|Leaflets apically 3-lobed, seldom undivided, largest usually 15–60 mm or more wide; filaments 1.5– 7.8 mm; Ontario to Ohio to Louisiana.
|[[#key-0-25| > 25]]
|-id=key-0-25
|25
|Anthers 0.5–1.5(–2.1) mm; stigma straight or distally coiled; flowers often bisexual.
|[[Thalictrum pubescens|Thalictrum pubescens]]
|-id=key-0-25
|25
|Anthers (0.7–)1–3.6 mm; stigma straight, ± filiform; flowers rarely bisexual (included here are very infrequent forms of T. dasycarpum and T. revolutum).
|[[#key-0-26| > 26]]
|-id=key-0-26
|26
|Leaflet length 0.9–5.25 times width; filaments 2.5–7.8 mm; anthers (0.7–)1.2– 2.7(–3) mm; stipe 0.2–1.7 mm; e North America, infrequent w of Missouri.
|[[Thalictrum amphibolum|Thalictrum amphibolum]]
|-id=key-0-26
|26
|Leaflet length 0.9–2.6 times width; filaments 2–6.5 mm; anthers 1–3.6(–4) mm; stipe 0–1.1 mm; w, c North America, very infrequent e of Ohio.
|[[Thalictrum dasycarpum|Thalictrum dasycarpum]]
|}
</div></div><!--

-->{{#Taxon:
name=Thalictrum
|author=Marilyn M. Park;Dennis Festerling Jr.
|authority=Linnaeus
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Ranunculaceae
|distribution=Nearly worldwide;mostly temperate
|reference=None
|publication title=Sp. Pl.;Gen. Pl. ed.
|publication year=;1754
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V3/V3_498.xml
|genus=Thalictrum
|beak architecture=coiled
|beak course=straight
|beak position or structure subtype=terminal
|beak presence=absent;absent
|beak some measurement=0mm;4mm
|caudex texture=woody
|cauline leaf arrangement=alternate
|distal leaf architecture=sessile
|filament shape=filiform;clavate or distally dilated
|flower architecture or arrangement or growth form=solitary
|flower architecture or shape=symmetric
|flower reproduction=unisexual;bisexual;bisexual
|flower sexes=unisexual
|flower some measurement=0cm;41cm
|fruit quantity=4;10
|fruits achene architecture=stipitate;sessile;aggregate
|fruits achene architecture or shape=discoid
|fruits achene shape=falcate;ovoid;obovoid
|inflorescence position=axillary
|inflorescence position or structure subtype=terminal
|involucral-bract architecture or shape=leaflike
|involucral-bract quantity=2;3
|involucre presence=absent;absent
|leaf position=cauline;basal
|leaf-blade architecture=compound
|leaflet shape=3-lobed;linear;lanceolate;linear;lanceolate;obovate;cordate-reniform
|margin shape=crenate;entire
|ovule quantity=1
|panicle architecture=(1-)2-200-flowered
|petal presence=absent
|pistil architecture=simple
|pistil quantity=1;16
|proximal leaf architecture=petiolate
|rhizome texture=woody
|root architecture=tuberous
|sepal coloration=whitish;greenish yellow or purplish
|sepal duration=not persistent
|sepal shape=lanceolate;reniform or spatulate
|sepal some measurement=1mm;18mm
|side architecture=ribbed;veined
|stamen quantity=7;30
|staminode presence=absent
|style presence=absent;absent
|whole_organism duration=perennial
|whole_organism growth form=herb
|x chromosome quantity=7
}}<!--

-->[[Category:Treatment]][[Category:Ranunculaceae]]