View source for Acaena

{{Treatment/ID
|accepted_name=Acaena
|accepted_authority=Mutis ex Linnaeus
|publications={{Treatment/Publication
|title=Mant. Pl.,
|place=145, 200. 1771
|year=1771
}}
|basionyms=
|synonyms=
|hierarchy=Rosaceae;Rosaceae subfam. Rosoideae;Rosaceae tribe Agrimonieae;Acaena
|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 Agrimonieae]]</div><div class="higher-taxon"><small>genus</small>[[Acaena]]</div></div>
|etymology=Greek akaina, thorn, alluding to barbed spines arising from wall of hypanthium
|volume=Volume 9
|mention_page=page 19, 312
|treatment_page=page 323
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Herbs,</b> perennial, 1–15 dm diam.; from branched, woody caudex or stoloniferous. <b>Stems</b> 1–20, creeping and rooting or suberect, basally woody, clad in old leaf bases, glabrous or sparsely pilose. <b>Leaves</b> persistent, basal and/or cauline; stipules absent or persistent, adnate to petiole, free portion ovate to obovate, deeply 2–5-fid, or linear, margins entire; petiole present; blade spatulate, [1–]2–15[–18] cm, herbaceous, leaflets 4–10 per side, opposite, ovate, oblong, or elliptic, margins flat or revolute, incised or pinnatisect, dentate or entire, surfaces hairy or glabrous. <b>Inflorescences</b> terminal or axillary, [4–]15–100-flowered, spikes or globose heads; peduncles present or absent; bracts absent; bracteoles present. <b>Pedicels</b> present. <b>Flowers</b> 3.5–6 mm diam.; hypanthium obtriangular, ovoid, or obconic, 3.5–6 mm diam., spiny [or winged or neither], tomentose or glabrous; sepals 4–5[–6], spreading, elliptic or triangular; petals 0; stamens 2–4[–6], longer than sepals; carpels 1[or 2], styles white or red, fimbriate. <b>Fruits</b> achenes, 1[–2], spindle-shaped; hypanthium persistent, enclosing achenes, gray- to red-brown, ovoid, oblong, globose, or obconic, 3–6 mm diam., hardened, sometimes winged, distinctly or obscurely angled with a single spine at apex of each of 4 angles, or covered with 10–20[–50] spines [or without spines], spines usually bearing retrorse hairs or barbs at apices, pubescent or glabrous, eglandular or glandular; sepals persistent, spreading. <b>x</b> = 21.</span><!--

-->{{Treatment/Body
|distribution=w United States;Mexico;South America (Argentina;Chile);s Africa (Cape Province);Atlantic Islands (Gough Island;South Georgia;Tristan da Cunha);Indian Ocean Islands (Kerguelen;Prince Edward Island);Pacific Islands (Hawaii;New Guinea;New Zealand);Australia;introduced in Europe (England;Ireland).
|discussion=<p>Species ca. 45 (3 in the flora).</p>
|tables=
|references={{Treatment/Reference
|id=bitter1910a
|text=Bitter, F. A. G. [1910–]1911. Die Gattung Acaena. Biblioth. Bot. 74.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Inflorescences interrupted spikes; fruiting hypanthia bearing 10–20 spines 1–3 mm; plants decumbent to suberect; leaflets pinnatisect.
|[[Acaena pinnatifida|Acaena pinnatifida]]
|-id=key-0-1
|1
|Inflorescences globose heads; fruiting hypanthia 4-angled, each angle with a spine at apex (arising distally) 7–15 mm; plants creeping or stoloniferous; leaflets dentate
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Fruiting hypanthia: spines 7–12 mm, without subsidiary spines on angles; stems 1.5–2 mm diam.; leaflet adaxial surfaces bright shining green, smooth, abaxial surfaces glaucescent.
|[[Acaena novae-zelandiae|Acaena novae-zelandiae]]
|-id=key-0-2
|2
|Fruiting hypanthia: spines 9–15 mm, with subsidiary spines on angles; stems 2–3 mm diam.; leaflet adaxial surfaces glossy green, rugulose, abaxial surfaces whitish with uneven wax layer.
|[[Acaena pallida|Acaena pallida]]
|}
</div></div><!--

-->{{#Taxon:
name=Acaena
|author=Bryony Macmillan
|authority=Mutis ex Linnaeus
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Rosaceae
|distribution=w United States;Mexico;South America (Argentina;Chile);s Africa (Cape Province);Atlantic Islands (Gough Island;South Georgia;Tristan da Cunha);Indian Ocean Islands (Kerguelen;Prince Edward Island);Pacific Islands (Hawaii;New Guinea;New Zealand);Australia;introduced in Europe (England;Ireland).
|reference=bitter1910a
|publication title=Mant. Pl.,
|publication year=1771
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse_grained_fna_xml/V9/V9_528.xml
|subfamily=Rosaceae subfam. Rosoideae
|tribe=Rosaceae tribe Agrimonieae
|genus=Acaena
}}<!--

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