View source for Psilactis

{{Treatment/ID
|accepted_name=Psilactis
|accepted_authority=A. Gray
|publications={{Treatment/Publication
|title=Mem. Amer. Acad. Arts, n. s.
|place=4: 71. 1849
|year=1849
}}
|basionyms=
|synonyms={{Treatment/ID/Synonym
|name=Machaeranthera sect. Psilactis
|authority=(A. Gray) B. L. Turner & D. B. Horne
}}
|hierarchy=Asteraceae;Asteraceae tribe Astereae;Psilactis
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Astereae]]</div><div class="higher-taxon"><small>genus</small>[[Psilactis]]</div></div>
|etymology=Greek psilos, bare, and actis, ray, alluding to epappose ray florets
|volume=Volume 20
|mention_page=page 11, 394, 458, 461, 466
|treatment_page=page 462
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals </b>or biennials [perennials], 15–150 cm (taprooted). <b>Stems</b> erect or weakly ascending, simple, glabrate to densely hairy and glandular. <b>Leaves</b>: basal and cauline (basal and proximal cauline withering and falling by flowering); alternate; petiolate, distal sessile; basal blades 1-nerved, obovate to linear-oblanceolate; proximal cauline blades lanceolate, elliptic, or obovate to linear-oblanceolate, margins entire, coarsely toothed or pinnately lobed, faces appressed-hairy; distal blades ovate to lanceolate to linear, smaller, margins entire, faces stipitate-glandular and/or appressed-hairy. <b>Heads</b> radiate, borne in loosely corymbiform arrays. <b>Involucres</b> turbinate to hemispheric, (2–9 ×) 4–18 mm. <b>Phyllaries</b> 30–45 in 2–3 series, (reflexed in fruit) 1-nerved (flat), oblong or lanceolate to linear, equal or unequal, herbaceous, bases usually indurate, margins scarious, herbaceous faces stipitate-glandular. <b>Receptacles</b> flat to convex, pitted to verrucose, epaleate. <b>Ray</b> florets 10–70, pistillate, fertile; corollas white to blue or purple (tightly coiled at maturity). <b>Disc</b> florets 15–150, bisexual, fertile (pappose); corollas yellow, lobes often purple, tubes shorter than funnelform throats, lobes 5, erect, deltate to lanceolate (glabrous or sparsely appressed-hairy). <b>Cypselae</b>: of ray fusiform to obovoid, of disc fusiform to clavate or obovoid, compressed, 5–18-nerved, faces sparsely to densely appressed-hairy (disc glabrate or glabrous in <i>P. heterocarpa</i>); pappi: ray 0; disc persistent, of 20–50, white to tawny, unequal, barbellate, apically attenuate bristles in 1–2 series. <b>x</b> = 3, 4, 9.</span><!--

-->{{Treatment/Body
|distribution=sw United States;Mexico;South America (Colombia;Peru).
|discussion=<p>Species 6 (5 in the flora).</p><!--
--><p>Molecular evidence from nuclear ribosomal DNA ITS and ETS sequences has indicated that <i>Psilactis</i> is closely related to <i>Symphyotrichum</i> (J. C. Semple et al. 2002; D. R. Morgan 1997, 2003).</p><!--
--><p><i>Psilactis</i> odysseus (G. L. Nesom) D. R. Morgan is the only species of the genus that does not occur in the flora area. It is found in the Mexican states of Nuevo León and Tamaulipas and is distinguished from the other five species by being a monocephalous, rhizomatous perennial.</p><!--
--><p><i>Arida</i> crispa and <i>A. coulteri</i> have been placed in <i>Psilactis</i> in the past because they have epappose ray florets (B. L. Turner and D. B. Horne 1964). They were placed in what is now <i>Arida</i> by R. L. Hartman (1990) because they produce flavones and have chromosome numbers of n = 5.</p>
|tables=
|references={{Treatment/Reference
|id=morgan1993b
|text=Morgan, D. R. 1993. A molecular systematic study and taxonomic revision of Psilactis (Asteraceae: Astereae). Syst. Bot. 18: 290–308.
}}{{Treatment/Reference
|id=turner1964a
|text=Turner, B. L. and D. B. Horne. 1964. Taxonomy of Machaeranthera sect. Psilactis (Compositae–Astereae). Brittonia 16: 316–331.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Involucres 2–4 mm; ray laminae 1–4 mm
|[[Psilactis brevilingulata|Psilactis brevilingulata]]
|-id=key-0-1
|1
|Involucres 4–8 mm; ray laminae 4–15 mm
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Phyllaries 0.3–0.7 mm wide; involucres broadly turbinate
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Phyllaries 0.6–1.2 mm wide; involucres hemispheric
|[[#key-0-4| > 4]]
|-id=key-0-3
|3
|Disc cypselae glabrate or glabrous, 2–3 mm, length 1.5–2 times ray cypselae
|[[Psilactis heterocarpa|Psilactis heterocarpa]]
|-id=key-0-3
|3
|Disc cypselae appressed-hairy, 1.5–2.5 mm, length 1–1.4 times ray cypselae
|[[Psilactis tenuis|Psilactis tenuis]]
|-id=key-0-4
|4
|Bases of distal cauline leaves cordate to auriculate, clasping; involucres 5–8 mm; receptacles 4–6 mm diam
|[[Psilactis gentryi|Psilactis gentryi]]
|-id=key-0-4
|4
|Bases of distal cauline leaves cuneate to slightly cordate, sometimes slightlyclasping; involucres 4–5 mm; receptacles 1.8–4 mm diam
|[[Psilactis asteroides|Psilactis asteroides]]
|}
</div></div><!--

-->{{#Taxon:
name=Psilactis
|author=David R. Morgan
|authority=A. Gray
|rank=genus
|parent rank=tribe
|synonyms=Machaeranthera sect. Psilactis
|basionyms=
|family=Asteraceae
|illustrator=Bee F. Gunn
|distribution=sw United States;Mexico;South America (Colombia;Peru).
|reference=morgan1993b;turner1964a
|publication title=Mem. Amer. Acad. Arts, n. s.
|publication year=1849
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse_grained_fna_xml/V19-20-21/V20_1067.xml
|tribe=Asteraceae tribe Astereae
|genus=Psilactis
}}<!--

-->[[Category:Treatment]][[Category:Asteraceae tribe Astereae]]