Difference between revisions of "Amphiachyris"
Trans. Amer. Philos. Soc., n. s. 7: 313. 1840.
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--><p><i>Amphiachyris</i> was recently treated within a more inclusive <i>Gutierrezia</i> (G. M. Diggs et al. 1999); apparently, it is more closely related to monotypic <i>Thurovia</i> than to <i>Gutierrezia</i> (Y. Suh and B. B. Simpson 1990). <i>Amphiachyris</i> is distinguished from <i>Gutierrezia</i> by a combination of glandular hairs only on the abaxial leaf faces, functionally staminate disc florets, disc pappi of basally connate, narrowly spatulate scales ± equaling corollas, and abaxial nerves of the phyllaries without green borders.</p> | --><p><i>Amphiachyris</i> was recently treated within a more inclusive <i>Gutierrezia</i> (G. M. Diggs et al. 1999); apparently, it is more closely related to monotypic <i>Thurovia</i> than to <i>Gutierrezia</i> (Y. Suh and B. B. Simpson 1990). <i>Amphiachyris</i> is distinguished from <i>Gutierrezia</i> by a combination of glandular hairs only on the abaxial leaf faces, functionally staminate disc florets, disc pappi of basally connate, narrowly spatulate scales ± equaling corollas, and abaxial nerves of the phyllaries without green borders.</p> | ||
|tables= | |tables= | ||
| − | |references= | + | |references={{Treatment/Reference |
| + | |id=lane1979a | ||
| + | |text=Lane, M. A. 1979. Taxonomy of the genus Amphiachyris (Asteraceae: Astereae). Syst. Bot. 4: 178–189. | ||
| + | }} | ||
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|illustration copyright=Flora of North America Association | |illustration copyright=Flora of North America Association | ||
|distribution=c United States. | |distribution=c United States. | ||
| − | |reference= | + | |reference=lane1979a |
|publication title=Trans. Amer. Philos. Soc., n. s. | |publication title=Trans. Amer. Philos. Soc., n. s. | ||
|publication year=1840 | |publication year=1840 | ||
|special status= | |special status= | ||
| − | |source xml=https:// | + | |source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V19-20-21/V20_167.xml |
|tribe=Asteraceae tribe Astereae | |tribe=Asteraceae tribe Astereae | ||
|genus=Amphiachyris | |genus=Amphiachyris | ||
Latest revision as of 20:00, 5 November 2020
Annuals, 20–100(–200) cm (glabrous, with strong terpenoid smell when crushed; taprooted). Stems erect, usually branched distally (bases usually lignescent). Leaves cauline; alternate; sessile; blades (1- or 3-nerved) linear to lanceolate, margins entire, faces gland-dotted. Heads radiate, in paniculiform or corymbiform arrays. Involucres narrowly campanulate to turbinate, 2–4 mm diam. Phyllaries 12–15 in 1–2(–3) series, 1-nerved (nerves without green margins) ovate, unequal, proximal 2/3 indurate, margins hyaline, faces whitish resinous. Receptacles flat to slightly convex, smooth (glabrous or hairy with multicellular, 1-seriate hairs), epaleate. Ray florets 7–12, pistillate, fertile; corollas yellow, sometimes drying orange-tinged. Disc florets 10–21, functionally staminate; corollas yellow, tubes shorter than cylindric throats, lobes 5, erect, deltate; style-branch appendages fused (pappi of 5–8 white, basally connate, linear, spatulate-tipped scales in 1 series, ± equaling corollas). Cypselae (ray, purplish black) obovoid-turbinate, plump, 4–9-ribbed (apices attenuate to slightly clavate), faces densely long- or short-setulose (hairs appressed, white), mostly occurring in lines between ribs; pappi coroniform. x = 4, 5.
Distribution
c United States.
Discussion
Species 2 (2 in the flora).
Amphiachyris was recently treated within a more inclusive Gutierrezia (G. M. Diggs et al. 1999); apparently, it is more closely related to monotypic Thurovia than to Gutierrezia (Y. Suh and B. B. Simpson 1990). Amphiachyris is distinguished from Gutierrezia by a combination of glandular hairs only on the abaxial leaf faces, functionally staminate disc florets, disc pappi of basally connate, narrowly spatulate scales ± equaling corollas, and abaxial nerves of the phyllaries without green borders.
Selected References
Lower Taxa
Key
| 1 | Plants 20–40(–60) cm; heads in open paniculiform arrays; cypselae 4–6-ribbed, long-setulose; leaf blades 0.2–1(–2) mm wide; receptacles with hooked, swollen-based hairs | Amphiachyris amoena |
| 1 | Plants 30–100(–200) cm; heads in crowded corymbiform arrays; cypselae 7–9-ribbed, short-setulose; leaf blades 0.5–6 mm wide; receptacles glabrous | Amphiachyris dracunculoides |