View source for Petalonyx

{{Treatment/ID
|accepted_name=Petalonyx
|accepted_authority=A. Gray
|publications={{Treatment/Publication
|title=Pl. Nov. Thurb.,
|place=319. 1854
|year=1854
}}
|common_names=Sandpaper plant
|basionyms=
|synonyms=
|hierarchy=Loasaceae;Petalonyx
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Loasaceae]]</div><div class="higher-taxon"><small>genus</small>[[Petalonyx]]</div></div>
|etymology=Greek petalon, petal, and onyx, claw, alluding to distinctive petal morphology
|volume=Volume 12
|mention_page=page 492, 544
|treatment_page=page 543
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Subshrubs </b>or shrubs; trichomes (1) pointed with surfaces ± smooth, notched, or antrorsely barbed, and (2) retrorsely barbed along shaft and at apex. <b>Stems</b> erect or spreading. <b>Leaves</b> cauline; petiole present or absent; blade ovate, elliptic, lanceolate, or falcate, unlobed, margins dentate, serrate, crenate, or entire. <b>Inflorescences</b> racemes or panicles; peduncle inconspicuous. <b>Pedicels</b> not elongating in fruit. <b>Flowers</b>: hypanthium adnate to ovary proximally, free distally; perianth whorls differentiated; sepals green, connate basally, lanceolate, shorter than petals; petals white, distinct or connate, spatulate or obovate, erect proximally, spreading to divaricate distally (corolla salverform or appearing so), glabrous except hairy abaxially on midribs; nectary distal on ovary; stamens 5, exserted, filaments monomorphic, filiform, longer than anthers; anthers without distal connective extension; staminodes absent [present]; pistil pseudomonomerous, placenta subapical; stigma lingulate, 2-lobed, papillate. <b>Fruits</b> cypselae, ±clavate, straight; sepals persistent. <b>Seeds</b> 1, ovoid. <b>x</b> = 23.</span><!--

-->{{Treatment/Body
|distribution=w United States;n Mexico.
|discussion=<p>Species 5 (4 in the flora).</p><!--
--><p><i>Petalonyx</i> belongs to subfam. Gronovioideae, which is characterized by relatively small flowers that have five stamens, one ovule, and indehiscent fruits. <i>Petalonyx</i> is most closely related to a clade that consists of <i>Cevallia</i>, Fuertesia Urban, and Gronovia Linnaeus (L. Hufford et al. 2003). <i>Petalonyx</i> crenatus A. Gray ex S. Watson, from Coahuila, Mexico, is the only species of the genus known only from outside the flora area; it can be distinguished from the species treated here by having two anther-bearing stamens and three shorter staminodes, rather than having five anther-bearing stamens.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Leaf blades usually elliptic, sometimes falcate, to 5 mm wide, margins entire; petal claws distinct; stamens exserted distally (not laterally between petal claws).
|[[Petalonyx linearis|Petalonyx linearis]]
|-id=key-0-1
|1
|Leaf blades ovate, or if elliptic then to 15–30 mm wide, margins usually serrate, dentate, or crenate, sometimes entire; petal claws postgenitally distally coherent; stamens exserted laterally through slits between petal claws.
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Petioles absent; leaf blades with marked size dimorphism, much larger on main stems than on fertile branches; petals to 6.5 mm.
|[[Petalonyx thurberi|Petalonyx thurberi]]
|-id=key-0-2
|2
|Petioles 0.5–4 mm; leaf blades without marked size dimorphism; petals 6–15 mm.
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Inflorescences 10–30-flowered; petals 6–11 mm; branches of current season 11–37 cm.
|[[Petalonyx nitidus|Petalonyx nitidus]]
|-id=key-0-3
|3
|Inflorescences 35–65-flowered; petals 10–15 mm; branches of current season to 13 cm.
|[[Petalonyx parryi|Petalonyx parryi]]
|}
</div></div><!--

-->{{#Taxon:
name=Petalonyx
|author=Larry Hufford
|authority=A. Gray
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Loasaceae
|distribution=w United States;n Mexico.
|reference=None
|publication title=Pl. Nov. Thurb.,
|publication year=1854
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/eaa6e58056e40c9ef614d8f47aea294977a1a5e9/coarse_grained_fna_xml/V12/V12_215.xml
|genus=Petalonyx
}}<!--

-->[[Category:Treatment]][[Category:Loasaceae]]