View source for Horkelia

{{Treatment/ID
|accepted_name=Horkelia
|accepted_authority=Chamisso & Schlechtendal
|publications={{Treatment/Publication
|title=Linnaea
|place=2: 26. 1827
|year=1827
}}
|basionyms=
|synonyms={{Treatment/ID/Synonym
|name=Potentilla sect. Horkelia
|authority=(Chamisso & Schlechtendal) Baillon
|rank=section
}} {{Treatment/ID/Synonym
|name=Potentilla subg. Horkelia
|authority=(Chamisso & Schlechtendal) Jepson
|rank=subgenus
}}
|hierarchy=Rosaceae;Rosaceae subfam. Rosoideae;Rosaceae tribe Potentilleae;Horkelia
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Rosaceae]]</div><div class="higher-taxon"><small>subfamily</small>[[Rosaceae subfam. Rosoideae]]</div><div class="higher-taxon"><small>tribe</small>[[Rosaceae tribe Potentilleae]]</div><div class="higher-taxon"><small>genus</small>[[Horkelia]]</div></div>
|etymology=For Johann Horkel, 1769–1846, German plant physiologist
|volume=Volume 9
|mention_page=page 120, 121, 122, 133, 219, 220, 243, 247, 248, 252, 256, 259, 264, 271, 281
|treatment_page=page 246
}}<!--

--><span class="statement" id="st-d0_s0" data-properties=""><b>Herbs,</b> perennial, rosetted, tufted, or matted, often resinously aromatic, 0.3–10 (–12) dm, sparsely to densely hairy, inconspicuously to conspicuously glandular;</span> <span class="statement" id="st-d0_s1" data-properties="whole_organism duration;whole_organism arrangement;whole_organism arrangement or pubescence;whole_organism growth form;whole_organism odor;whole_organism atypical some measurement;whole_organism some measurement;whole_organism pubescence;whole_organism pubescence;whole_organism architecture;whole_organism growth form">compactly to ± loosely rhizomatous.</span> <span class="statement" id="st-d0_s2" data-properties="stem quantity;stem orientation;stem growth form or orientation;stem coloration;stem coloration;stem coloration;stem coloration;stem coloration"><b>Stems </b>1–10+, decumbent to erect, rarely prostrate, green, reddish, or stramineous.</span> <span class="statement" id="st-d0_s3" data-properties="leaf condition;leaf duration;leaf position;cauline leaf atypical quantity;cauline leaf quantity;cauline leaf size;cauline leaf arrangement;cauline leaf architecture"><b>Leaves </b>marcescent or winter-persistent, primarily basal, cauline 1–6 (–10), gradually or abruptly reduced distally, alternate, odd-pinnate;</span> <span class="statement" id="st-d0_s4" data-properties="stipule duration;stipule fusion;stipule shape;margin shape;margin shape;segment shape">stipules persistent, basally adnate to petiole, linear to lanceolate or elliptic, margins entire or pinnately divided into linear to filiform segments;</span> <span class="statement" id="st-d0_s5" data-properties="petiole presence">petiole present;</span> <span class="statement" id="st-d0_s6" data-properties="blade shape;blade shape;blade atypical some measurement;blade atypical some measurement;blade some measurement;blade architecture;leaflet atypical quantity;leaflet quantity;leaflet arrangement;leaflet arrangement;leaflet arrangement;leaflet position or structure subtype;leaflet arrangement;leaflet shape;distalmost leaflet position;margin shape;margin shape;margin architecture or shape;margin architecture or shape;margin architecture;lobe shape;apex shape">blade oblanceolate-oblong to linear in outline, planar to cylindric, (1–) 2–30 (–40) cm, foliaceous, leaflets (3–) 5–41, separate or congested and overlapping, terminal usually ± confluent with distalmost lateral ones, elliptic-oblong to ovate or flabellate in outline, margins flat, shallowly toothed to deeply divided into oblanceolate lobes, sometimes nearly entire except for 3-toothed apex, rarely completely entire, venation palmate to pinnate.</span> <span class="statement" id="st-d0_s7" data-properties="inflorescence position or structure subtype;inflorescence architecture;cyme architecture;flower arrangement;flower architecture or shape;glomerule architecture;glomerule arrangement;glomerule shape"><b>Inflorescences </b>terminal, 3–200-flowered, open to congested cymes, flowers arranged individually, in corymbiform clusters, and/or in ± globose glomerules, these sometimes capitate;</span> <span class="statement" id="st-d0_s8" data-properties="bract presence;bract architecture;bract size">bracts present at proximal nodes, ± leafy, becoming reduced distally;</span> <span class="statement" id="st-d0_s9" data-properties="bracteole presence">bracteoles absent.</span> <span class="statement" id="st-d0_s10" data-properties="pedicel presence;pedicel course;pedicel orientation;pedicel orientation"><b>Pedicels </b>present, usually straight in fruit, sometimes reflexed or recurved.</span> <span class="statement" id="st-d0_s11" data-properties="flower diameter"><b>Flowers </b>4–17 mm diam.;</span> <span class="statement" id="st-d0_s12" data-properties="epicalyx bractlet quantity">epicalyx bractlets 5;</span> <span class="statement" id="st-d0_s13" data-properties="hypanthium shape;hypanthium some measurement;hypanthium quantity;base shape;interior width">hypanthium ± cupulate with flattened bases, 1–5.5 mm, less than 1/2 to nearly as deep as wide, interior often with band of hairs;</span> <span class="statement" id="st-d0_s14" data-properties="sepal quantity;sepal orientation;sepal shape;sepal shape">sepals 5, spreading to strongly reflexed, usually lanceolate, sometimes ovate to triangular;</span> <span class="statement" id="st-d0_s15" data-properties="petal quantity;petal coloration;petal coloration;petal architecture;petal coloration;petal shape;petal shape;petal variability;petal length or size">petals 5, usually white, sometimes pink to rose-veined or cream, usually narrowly oblanceolate-elliptic to obovate, sometimes linear to round, usually equal to or longer than sepals;</span> <span class="statement" id="st-d0_s16" data-properties="stamen quantity;stamen height or length or size;filament orientation;filament shape;anther theca dehiscence">stamens 10, shorter than petals, filaments usually ± erect, ± flattened, forming tube, anther thecae dehiscing introrsely;</span> <span class="statement" id="st-d0_s17" data-properties="torus shape">torus conic;</span> <span class="statement" id="st-d0_s18" data-properties="carpel atypical quantity;carpel quantity;carpel pubescence;style position">carpels 2–200 (–220), glabrous, styles subterminal;</span> <span class="statement" id="st-d0_s19" data-properties="ovule quantity">ovule 1.</span> <span class="statement" id="st-d0_s20" data-properties="fruit shape;fruit some measurement;fruit pubescence;achene arrangement;achene atypical quantity;achene atypical quantity;achene quantity"><b>Fruits </b>aggregated achenes, (1–) 2–200 (–220), obliquely ovoid to reniform, 0.8–3 mm, glabrous;</span> <span class="statement" id="st-d0_s21" data-properties="hypanthium duration">hypanthium persistent;</span> <span class="statement" id="st-d0_s22" data-properties="sepal duration;sepal orientation">sepals persistent, erect;</span> <span class="statement" id="st-d0_s23" data-properties="">styles tardily deciduous, jointed, usually ± rough-thickened basally, otherwise mostly filiform.</span> <span class="statement" id="st-d0_s24" data-properties="style duration;style architecture;style size or width;style shape;x chromosome quantity">x = 7.</span><!--

-->{{Treatment/Body
|distribution=w North America;nw Mexico
|discussion=<p>Species 20 (20 in the flora).</p><!--
--><p>As discussed under 9. Ivesia, recognition of the ivesioid genera including Horkelia results in a paraphyletic Potentilla, which the first author does not find sufficient to dictate generic circumscriptions. On the basis of morphology and biogeography, Horkelia itself is likely nested within Ivesia as the branch that has radiated primarily within the California Floristic Province (see discussions under Ivesia regarding discordance with M. Töpel et al. 2012, http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0050358). Ivesia in the strict sense consists of an exceptionally diverse array of well-defined species; in contrast, Horkelia is more morphologically coherent as a genus but with species less sharply defined. The primary unifying features of the genus result from a flower specifically adapted for bee pollination: a relatively deep, flat-bottomed hypanthium containing abundant nectar, to which access is restricted by the columnar arrangement of ten erect stamens with flattened filaments, at least in early flowering. Anthers open introrsely by adaxial slits so that pollen is deposited on a visitor forcing its way into the staminal column.</p><!--
--><p>Other diagnostic characteristics of Horkelia include a distinctive resinous aroma in most species (except sect. Tridentatae and sect. Hispidulae) and various levels of glandularity. The terminal leaflet is most often lobed and/or confluent with lateral leaflets, in contrast to Drymocallis, which is often confused with Horkelia. Leaves range from planar with distinct leaflets to cylindric with overlapping leaflets, the latter condition often a response to drought stress in species that are normally planar-leaved. Sepals are often strongly reflexed.</p><!--
--><p>Stem lengths given below include inflorescences. Leaflet descriptions are based primarily on mid rachis leaflets of the larger basal leaves present at flowering; leaflets on the smaller outermost leaves formed early in the growing season are often less divided and less hairy. Counts of leaflet marginal segments include both shallow (teeth) and deep (lobes) ultimate divisions. Flowers are often aggregated into a single corymbiform cluster or one to many more globular glomerules, some of which are tightly capitate. Hypanthia interiors are glabrous in most species, except for the hairs surrounding the torus; some taxa are also more or less pilose on the internal hypanthial walls, especially just below the rim. Sepals are described as spreading or reflexed based on their orientation at anthesis. Larger and smaller anthers often are alternating; measurements are primarily of the larger filaments, with width measured at the base. See under 8. Potentilla and 9. Ivesia for additional discussion of special terminology.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Pedicels becoming reflexed or recurved, 3–15 mm; inflorescences open; Sierra Nevada foothills and San Bernardino Mountains, California.
|[[Horkelia sect. Parryae|Horkelia sect. Parryae]]
|-id=key-0-1
|1
|Pedicels remaining straight, outermost sometimes ± reflexed in congested inflorescences, 1–30(–40) mm; inflorescences open to congested; w United States
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Basal leaves: leaflet teeth (0–)3(–5), restricted to apex, leaflets 2–5 per side.
|[[Horkelia sect. Tridentatae|Horkelia sect. Tridentatae]]
|-id=key-0-2
|2
|Basal leaves: leaflet teeth or lobes (0–)4–30(–60), not restricted to apex, leaflets (1–)3–16(–20) per side
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Plants not resinously aromatic, inconspicuously to moderately glandular; basal leaves ± cylindric to weakly planar; leaflets ± overlapping at least distally, divided 1/2–3/4+ to midrib into (0–)2–8(–15) lobes
|[[#key-0-4| > 4]]
|-id=key-0-3
|3
|Plants ± resinously aromatic, conspicuously to obscurely (and minutely) glandular; leaves usually ± planar, sometimes nearly cylindric; leaflets separate to ± overlapping especially distally, divided ± 1/6–3/4+ to midrib into (3–)5–30(–60) teeth or lobes
|[[#key-0-5| > 5]]
|-id=key-0-4
|4
|Plants forming dense mats; stems 0.3–2.5 dm; basal leaves: stipules entire; 2000–3400 m; White Mountains, s Sierra Nevada, and Siskiyou Mountains, California, w Nevada, sw Oregon.
|[[Horkelia sect. Hispidulae|Horkelia sect. Hispidulae]]
|-id=key-0-4
|4
|Plants forming rosettes or tufts, sometimes loose mats; stems 0.5–5 dm; basal leaves: stipules entire, forked, or pinnately divided into linear or filiform lobes; 60–2500 m; nw California, sw Oregon.
|[[Horkelia sect. Tridentatae|Horkelia sect. Tridentatae]]
|-id=key-0-5
|5
|Epicalyx bractlets narrowly elliptic-lanceolate to broadly ovate, 0.5–3 mm wide; pedicels 1–30(–40) mm; flowers arranged individually, in usually non-capitate glomerules, and/or in corymbiform clusters; Sierra Nevada foothills and w California.
|[[Horkelia sect. Horkelia|Horkelia sect. Horkelia]]
|-id=key-0-5
|5
|Epicalyx bractlets linear, 0.2–0.3(–0.5) mm wide; pedicels 1–3(–10) mm; flowers usually arranged in ± capitate glomerules, rarely individually (in H. fusca var. filicoides); Sierra Nevada, California, to Washington and Wyoming.
|[[Horkelia sect. Capitatae|Horkelia sect. Capitatae]]
|}
</div></div><!--

-->{{#Taxon:
name=Horkelia
|author=Barbara Ertter;James L. Reveal
|authority=Chamisso & Schlechtendal
|rank=genus
|parent rank=tribe
|synonyms=Potentilla sect. Horkelia;Potentilla subg. Horkelia
|basionyms=
|family=Rosaceae
|distribution=w North America;nw Mexico
|reference=None
|publication title=Linnaea
|publication year=1827
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V9/V9_385.xml
|subfamily=Rosaceae subfam. Rosoideae
|tribe=Rosaceae tribe Potentilleae
|genus=Horkelia
|achene arrangement=aggregated
|achene atypical quantity=200;220
|achene quantity=2;200
|anther theca dehiscence=dehiscing
|apex shape=3-toothed
|base shape=flattened
|blade architecture=foliaceous
|blade atypical some measurement=30cm;40cm
|blade shape=planar;cylindric
|blade some measurement=2cm;30cm
|bract architecture=leafy
|bract presence=absent
|bract size=reduced
|bracteole presence=absent
|carpel atypical quantity=200;220
|carpel pubescence=glabrous
|carpel quantity=2;200
|cauline leaf architecture=odd-pinnate
|cauline leaf arrangement=alternate
|cauline leaf atypical quantity=6;10
|cauline leaf quantity=1;6
|cauline leaf size=reduced
|cyme architecture=open to congested
|distalmost leaflet position=lateral
|epicalyx bractlet quantity=5
|filament orientation=erect
|filament shape=flattened
|flower architecture or shape=capitate
|flower arrangement=arranged
|flower diameter=4mm;17mm
|fruit pubescence=glabrous
|fruit shape=obliquely ovoid;reniform
|fruit some measurement=0.8mm;3mm
|glomerule architecture=corymbiform
|glomerule arrangement=cluster
|glomerule shape=globose
|hypanthium duration=persistent
|hypanthium quantity=0;1/2
|hypanthium shape=cupulate
|hypanthium some measurement=1mm;5.5mm
|inflorescence architecture=3-200-flowered
|inflorescence position or structure subtype=terminal
|interior width=wide
|leaf condition=marcescent
|leaf duration=winter-persistent
|leaf position=basal
|leaflet arrangement=confluent;overlapping;congested;separate
|leaflet atypical quantity=3;5
|leaflet position or structure subtype=terminal
|leaflet quantity=5;41
|leaflet shape=elliptic-oblong;ovate or flabellate
|lobe shape=oblanceolate
|margin architecture=palmate;pinnate
|margin architecture or shape=entire;entire
|margin shape=shallowly toothed;deeply divided
|ovule quantity=1
|pedicel course=straight
|pedicel orientation=recurved;reflexed
|pedicel presence=absent
|petal architecture=rose-veined
|petal coloration=cream;pink;white
|petal length or size=longer
|petal quantity=5
|petal shape=linear;round
|petal variability=equal
|petiole presence=absent
|segment shape=linear;filiform
|sepal duration=persistent
|sepal orientation=erect;spreading;strongly reflexed
|sepal quantity=5
|sepal shape=ovate;triangular
|stamen height or length or size=shorter
|stamen quantity=10
|stem coloration=stramineous;reddish;stramineous;reddish;green
|stem growth form or orientation=prostrate
|stem orientation=decumbent;erect
|stem quantity=1;10
|stipule duration=persistent
|stipule fusion=adnate
|stipule shape=linear;lanceolate or elliptic
|style architecture=jointed
|style duration=deciduous
|style position=subterminal
|style shape=filiform
|style size or width=rough-thickened
|torus shape=conic
|whole_organism architecture=rhizomatous
|whole_organism arrangement=rosetted
|whole_organism arrangement or pubescence=tufted
|whole_organism atypical some measurement=10dm;12dm
|whole_organism duration=perennial
|whole_organism growth form=herb;matted
|whole_organism odor=aromatic
|whole_organism pubescence=hairy;inconspicuously conspicuously glandular
|whole_organism some measurement=0.3dm;10dm
|x chromosome quantity=7
}}<!--

-->[[Category:Treatment]][[Category:Rosaceae tribe Potentilleae]]