View source for Descurainia nelsonii

{{Treatment/ID
|accepted_name=Descurainia nelsonii
|accepted_authority=(Rydberg) Al-Shehbaz & Goodson
|publications={{Treatment/Publication
|title=Harvard Pap. Bot.
|place=12: 422. 2007
|year=2007
}}
|basionyms={{Treatment/ID/Basionym
|name=Sophia nelsonii
|authority=Rydberg
|rank=species
|publication_title=Bull. Torrey Bot. Club
|publication_place=34: 436. 1907
}}
|synonyms={{Treatment/ID/Synonym
|name=Descurainia brachycarpa var. nelsonii
|authority=(Rydberg) O. E. Schulz
|rank=variety
}} {{Treatment/ID/Synonym
|name=Descurainia pinnata subsp. nelsonii
|authority=(Rydberg) Detling
|rank=subspecies
}} {{Treatment/ID/Synonym
|name=Descurainia pinnata var. nelsonii
|authority=(Rydberg) M. Peck
|rank=variety
}}
|hierarchy=Brassicaceae;Brassicaceae tribe Descurainieae;Descurainia;Descurainia nelsonii
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Brassicaceae]]</div><div class="higher-taxon"><small>tribe</small>[[Brassicaceae tribe Descurainieae]]</div><div class="higher-taxon"><small>genus</small>[[Descurainia]]</div><div class="higher-taxon"><small>species</small>[[Descurainia nelsonii]]</div></div>
|volume=Volume 7
|mention_page=page 520, 526
|treatment_page=page 525
}}<!--

--><span class="statement" id="st-undefined" data-properties="">Annuals; eglandular; sparsely to moderately pubescent, sometimes glabrous distally, not canescent, trichomes dendritic. <b>Stems</b> erect, usually branched basally or slightly distally, rarely unbranched, (0.7–)0.9–3.2(–4.5) dm. <b>Basal</b> leaves: petiole 0.5–1.5 cm; blade pinnate, ovate or oblong in outline, 0.8–2.5 cm, lateral lobe (2–5 pairs), margins dentate or entire. <b>Cauline</b> leaves sessile or shortly petiolate; blade smaller distally, distal lobes often narrower, sparsely to moderately pubescent. <b>Racemes</b> considerably elongated in fruit. <b>Fruiting</b> pedicels divaricate-ascending (often at 20–45º angle), straight, (1.5–)2.5–7(–10) mm. <b>Flowers</b>: sepals ascending, yellowish, oblong, 0.7–1.2 mm, pubescent; petals narrowly oblanceolate, 0.8–1.2 × 0.2–0.4 mm; median filaments 1–1.5 mm; anthers 0.1–0.2 mm. <b>Fruits</b> erect or ascending, linear, not or slightly torulose, (0.4–)5–8(–10) × 0.7–1 mm; valves each with distinct midvein; septum not veined; ovules 6–12 per ovary; style 0.1–0.2 mm, glabrous. <b>Seeds</b> uniseriate, brown, oblong, 0.6–0.8 × 0.4–0.5 mm. <b>2n</b> = 14.</span><!--

-->{{Treatment/Body
|phenology=Flowering late May-mid Jul.
|habitat=Roadsides, sagebrush, wash bottoms, silty flats, gravelly grounds
|elevation=800-3000 m
|distribution=B.C.;Calif.;Idaho;Mont.;Nev.;Oreg.;Wash.;Wyo.
|discussion=<p><i>Descurainia nelsonii</i> was treated by L. E. Detling (1939) and R. C. Rollins (1993) as a subspecies of <i>D. pinnata</i>, but the latter in the sense of these authors is not monophyletic, comprising instead either four or two unrelated species, respectively. ITS molecular data (B. E. Goodson 2007) suggest that <i>D. nelsonii</i> is most closely related to <i>D. longepedicellata</i> and <i>D. paradisa</i>. It can be distinguished from the latter species by its linear fruits with cuneate tips; <i>D. paradisa</i> has obovoid fruits with rounded tips. <i>Descurainia nelsonii</i> resembles <i>D. pinnata </i>subsp.<i> brachycarpa</i> in the orientation of fruiting pedicels and in having short styles (to 0.3 mm) and small seeds (to 1 × 0.5 mm). It differs in being branched (versus simple) at base and in having smaller flowers (petals 0.7–1 versus 1.5–2.6 mm), fewer ovules (6–12 versus 16–40) per ovary, linear (versus subclavate) fruits, and uniseriate (versus biseriate) seeds.</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Descurainia nelsonii
|authority=(Rydberg) Al-Shehbaz & Goodson
|rank=species
|parent rank=genus
|synonyms=Descurainia brachycarpa var. nelsonii;Descurainia pinnata subsp. nelsonii;Descurainia pinnata var. nelsonii
|basionyms=Sophia nelsonii
|family=Brassicaceae
|phenology=Flowering late May-mid Jul.
|habitat=Roadsides, sagebrush, wash bottoms, silty flats, gravelly grounds
|elevation=800-3000 m
|distribution=B.C.;Calif.;Idaho;Mont.;Nev.;Oreg.;Wash.;Wyo.
|reference=None
|publication title=Harvard Pap. Bot.
|publication year=2007
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f50eec43f223ca0e34566be0b046453a0960e173/coarse_grained_fna_xml/V7/V7_827.xml
|tribe=Brassicaceae tribe Descurainieae
|genus=Descurainia
|species=Descurainia nelsonii
}}<!--

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