View source for Mentzelia pachyrhiza

{{Treatment/ID
|accepted_name=Mentzelia pachyrhiza
|accepted_authority=I. M. Johnston
|publications={{Treatment/Publication
|title=J. Arnold Arbor.
|place=21: 71. 1940
|year=1940
}}
|common_names=Big-rooted stickleaf
|basionyms=
|synonyms=
|hierarchy=Loasaceae;Mentzelia;Mentzelia sect. Mentzelia;Mentzelia pachyrhiza
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Loasaceae]]</div><div class="higher-taxon"><small>genus</small>[[Mentzelia]]</div><div class="higher-taxon"><small>section</small>[[Mentzelia sect. Mentzelia]]</div><div class="higher-taxon"><small>species</small>[[Mentzelia pachyrhiza]]</div></div>
|volume=Volume 12
|mention_page=page 527, 530
|treatment_page=page 529
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Plants </b>perennial, with tubers. <b>Stems</b> erect, to 50 cm. <b>Leaves</b>: petiole mostly 3–20 mm, less than 3 mm only on smallest, distalmost leaves; blade ovate to hastate, basally lobed or unlobed, to 4 × 3 cm, base usually acute to obtuse, sometimes attenuate or hastate, margins usually serrate, sometimes crenate, apex acute. <b>Pedicels</b> (fruiting) (0–)2 × 2 mm. <b>Flowers</b>: petals orange, 5–11.5 × 3–5 mm, apex acute to rounded, hairy abaxially on distal 1/2; stamens 15–45, 4–8 mm, filaments usually monomorphic, filiform, rarely heteromorphic, outermost slightly spatulate, inner filiform; style 3–7.5 mm. <b>Capsules</b> subcylindric to clavate, 6–10 × 1.5–2.3 mm, base tapering gradually, capsule and pedicel not well-differentiated, walls thin, brittle. <b>Seeds</b> 2–3 per capsule, oblong, with transverse folds. <b>2n</b> = 22.</span><!--

-->{{Treatment/Body
|phenology=Flowering May–Nov.
|habitat=Steep limestone cliffs, gravelly slopes of gypseous clayey soils, desert scrub and Larrea communities.
|elevation=900–2000 m.
|distribution=Tex.;Mexico (Chihuahua;Coahuila;Durango;Nuevo León).
|discussion=<p><i>Mentzelia pachyrhiza</i>, native to the Chihuahuan Desert, reaches the flora area only in southern Brewster and Presidio counties. In southwestern Texas and northeastern Chihuahua, where <i>M. pachyrhiza</i> and <i>M. oligosperma</i> have overlapping ranges, H. J. Thompson and A. M. Powell (1981) reported that the former was found at elevations usually below 1100 meters in the <i>Larrea</i> zone, below the elevation of junipers and <i>M. oligosperma</i>. Thompson and Powell allied <i>M. pachyrhiza</i> with <i>M. oligosperma</i> and the South American M. grisebachii Urban & Gilg, now treated as a synonym of <i>M. parvifolia</i> Urban & Gilg ex Kurtz (M. Weigend 2007b). This placement is consistent with phylogenetic studies (J. Grissom and L. Hufford, unpubl.), which show that <i>M. pachyrhiza</i> is the sister species of <i>M. parvifolia</i>; they together are the sister of <i>M. oligosperma</i> and the Mexican M. pattersonii B. L. Turner. I. M. Johnston’s (1940) assertion that the large tuber of <i>M. pachyrhiza</i> is unique in sect. <i>Mentzelia</i> is incorrect. Tubers, often carrot-shaped, are common among the perennial species of the section.</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Mentzelia pachyrhiza
|authority=I. M. Johnston
|rank=species
|parent rank=section
|synonyms=
|basionyms=
|family=Loasaceae
|phenology=Flowering May–Nov.
|habitat=Steep limestone cliffs, gravelly slopes of gypseous clayey soils, desert scrub and Larrea communities.
|elevation=900–2000 m.
|distribution=Tex.;Mexico (Chihuahua;Coahuila;Durango;Nuevo León).
|reference=None
|publication title=J. Arnold Arbor.
|publication year=1940
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/eaa6e58056e40c9ef614d8f47aea294977a1a5e9/coarse_grained_fna_xml/V12/V12_568.xml
|genus=Mentzelia
|section=Mentzelia sect. Mentzelia
|species=Mentzelia pachyrhiza
}}<!--

-->[[Category:Treatment]][[Category:Mentzelia sect. Mentzelia]]