Chaenactis

de Candolle in A. P. de Candolle and A. L. P. P. de Candolle

in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 659. 1836.

Common names: Pincushion dustymaidens
Etymology: Greek chaino, to gape, and aktis, ray, alluding to enlarged peripheral corollas of type species
Treatment appears in FNA Volume 21. Treatment on page 400. Mentioned on page 5, 182, 364, 365, 366, 395, 401, 402.
 TaxonIllustrator 
FNA21 P62 Hulsea heterochroma.jpegHulsea vestita subsp. pygmaea
Chaenactis carphoclinia var. carphoclinia
Hulsea heterochroma
Yevonn Wilson-Ramsey
Linny Heagy
Yevonn Wilson-Ramsey
FNA21 P63 Chaenactis douglasii.jpegChaenactis douglasii var. douglasii
Chaenactis douglasii var. alpina
Chaenactis xantiana
Chaenactis stevioides
Orochaenactis thysanocarpha
Linny Heagy
Linny Heagy
Linny Heagy
Linny Heagy
John Myers

Annuals, biennials, perennials, or subshrubs, (2–) 5–70 (–200) cm (taprooted). Stems erect to prostrate, usually branched. Leaves basal and/or cauline (smaller and sparser distally except in C. cusickii); alternate; usually petiolate; blades deltate, elliptic, linear, oblanceolate, or ovate (plane or ± 3-dimensional), (0–) 1–4-pinnately (rarely -subpalmately) lobed, ultimate margins entire, faces glabrous or hairy, often stipitate-glandular or glanddotted. Heads discoid or ± radiant, borne singly or in (terminal) ± cymiform arrays (erect in bud except C. macrantha). Involucres hemispheric to obconic or broadly cylindric, (3–) 5–15 [–25] mm diam. Phyllaries 5–21+ in 1–2 (–3) series (subequal to unequal). Receptacles convex to ± flat, pitted and/or knobby, usually epaleate (paleae 3–10+ in C. carphoclinia). Ray-florets 0 (sometimes simulated by enlarged peripheral disc corollas). Disc-florets 8–70+, bisexual, fertile (diurnal with anthers exserted except in C. macrantha); corollas white, pinkish, cream, or yellow, tubes shorter than cylindric or funnelform throats, lobes 5, deltate to ± lanceolate (sometimes enlarged, unequal; style-branch appendages blunt, obscure). Cypselae clavate to ± cylindric or compressed, obscurely 8–20-angled, faces scabrous and strigose to densely sericeous (usually eglandular); pappi usually persistent, of (1–) 4–20, distinct, ± erose scales in 1–4 series (equal or unequal, outer then shorter, scales usually fewer and/or shorter on peripheral cypselae, midnerves obscure), sometimes 0 or coroniform. x = ? (n = 6, 8, plus polyploids and dysploid numbers).

Distribution

w North America, nw Mexico

Discussion

Species 18 (17 in the flora).

Chaenactis species grow in arid to alpine or Mediterranean climates, usually in open, unstable or early seral habitats (loose sand, scree, talus, shrink-swell clay, fire-adapted vegetation, recent disturbances). Some annual species have been grown in gardens in the eastern United States.

Differences in induments are key to distinguishing some Chaenactis species. Unless otherwise noted in descriptions and key leads, assume for any given plant that indument of proximal leaves and adjacent proximal portions of stems (“proximal indument”) is similar; indument of distal leaves is, likewise, similar to indument of stem portions from which they arise; peduncle indument is denser distally than proximally; and distal peduncle indument is similar to proximal phyllary indument. Unless otherwise noted, phyllary traits apply to the outer series only. Pappus scales may be equal, subequal, or unequal; unequal scales may intergrade (here said to be in gradually unequal series) or may form two, more or less uniform, shorter and longer series (here said to be in abruptly unequal series); subequal scales are said to be in subequal series. Excellent illustrations of most Chaenactis species appeared in L. Abrams and R. S. Ferris (1923–1960, vol. 4) and A. Cronquist (1955).

Section Acarphaea is distinctive by its farinose indument and base chromosome number of 8, among other traits; it could prove to be a separate, convergent genus. Natural and artificial hybrids have been documented among some members of sect. Chaenactis (see further discussion there). Reports of hybrids among species of the other two sections are few and doubtful. Chaenactis appears to be most closely related to the monotypic Dimeresia and Orochaenactis, which B. G. Baldwin et al. (2002) treated together as a narrowly circumscribed tribe, Chaenactideae.

Key

1 Annuals; proximal indument predominantly ± farinose, not arachnoid; largest leaf blades (2–)3–4-pinnately lobed Chaenactis sect. Acarphaea
1 Annuals, biennials, perennials, or subshrubs; proximal indument predominantly arachnoid, lanuginose, pannose, stipitate-glandular, or glabrescent, not farinose; largest leaf blades (0–)1–2-pinnately or -subpalmately lobed > 2
2 Biennials, perennials, or subshrubs (rarely flowering first year); pappi of (8–)10–20 scales in 2–4 equal or gradually unequal series; leaf blades gland-dotted beneath indument Chaenactis sect. Macrocarphus
2 Annuals; pappi usually of (1–)4–8(–14) scales in 1, 2 abruptly unequal, or 2–3 gradually unequal series, sometimes 0 or coroniform; leaf blades not gland-dotted (except C. macrantha) Chaenactis sect. Chaenactis
... more about "Chaenactis"
not tailed +, rounded +  and obtuse +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
paniculiform +, cymiform +  and corymbiform +
indeterminate +  and determinate +
James D. Morefield +
de Candolle in A. P. de Candolle and A. L. P. P. de Candolle +
decurrent +
compound +  and simple +
lobed;ovate;oblanceolate;ovate;oblanceolate;linear;deltate +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
connate +  and distinct +
Pincushion +  and dustymaidens +
yellow +, cream +, pinkish +  and white +
stipitate-glandular +  and hairy +
8-20-angled +, clavate +  and more or less cylindric or compressed +
fertile +  and bisexual +
fertile +  and bisexual +
w North America +  and nw Mexico +
Greek chaino, to gape, and aktis, ray, alluding to enlarged peripheral corollas of type species +
strigose +  and densely sericeous +
scabrellous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
campanulate +  and cylindric +
in more or less cymiform arrays +, singly +  and radiant +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
hemispheric;obconic or broadly cylindric +
cauline +  and basal +
deltate +  and more or less lanceolate +
dentate to pinnatifid or palmatifid +  and entire +
2-carpellate +
persistent +
coroniform +
5 +  and 21 +
in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. +
bearing subulate enations +, hairy +  and bristly +
knobby;convex;more or less flat +
mooring1965a +  and stockwell1940a +
distinct +
4 +  and 20 +
exalbuminous +
erect +  and prostrate +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Undefined (tribe Undefined) subtribe Bahiinae +  and Undefined (tribe Undefined) subtribe Palafoxiinae +
Chaenactis +
Asteraceae (tribe Heliantheae) subtribe Chaenactidinae +
cylindric +
80 cm800 mm <br />0.8 m <br /> (300 cm3,000 mm <br />3 m <br />) +
1 cm10 mm <br />0.01 m <br /> (80 cm800 mm <br />0.8 m <br />) +
toothed +  and entire +
70 cm700 mm <br />0.7 m <br /> (200 cm2,000 mm <br />2 m <br />) +
perennial +, biennial +  and annual +
5 cm50 mm <br />0.05 m <br /> (70 cm700 mm <br />0.7 m <br />) +