Chaenactis macrantha

D. C. Eaton in S. Watson

in S. Watson, Botany (Fortieth Parallel), 171, plate 18, figs. 1–5. 1871.

Common names: Showy or bighead dustymaidens Mojave pincushion
Endemic
Treatment appears in FNA Volume 21. Treatment on page 410. Mentioned on page 400, 401, 408, 409.

Plants 5–25 (–35) cm; proximal indument grayish, arachnoid-sericeous to closely lanuginose (sometimes tardily glabrescent). Stems mostly 1–5; branches mainly proximal. Leaves basal (withering) and cauline, 1.5–7 cm; largest blades ± elliptic to ovate, ± plane, not succulent, 1 (–2) -pinnately lobed (± glanddotted beneath indument); primary lobes mostly 2–5 pairs, ± remote, ultimate lobes ± plane. Heads (± radiant, nocturnally), mostly 1–5 (–7) per stem (nodding in bud). Peduncles 1.5–8 cm, arachnoid-sericeous to thinly lanuginose distally, not stipitate-glandular. Involucres ± obconic to broadly cylindric. Phyllaries: longest 12–18 mm; outer arachnoid-sericeous to thinly lanuginose in fruit, not stipitate-glandular, apices ± squarrose, blunt, pliant. Florets: corollas (nocturnal) white to pinkish or cream, 9–12 (–15) mm (lengths 1.8–2.2 times cypselae; anthers ± included); peripheral corollas nocturnally spreading, actinomorphic, scarcely enlarged. Cypselae 5–6 (–7) mm; pappi of 8 scales in 2, abruptly unequal series, longest scales 5–7 mm. 2n = 12.


Phenology: Flowering Mar–early Jul.
Habitat: Open, loose, light-colored, silty, usually calcareous or alkaline, desert soils, often covered by or mixed with gravel
Elevation: 600–2200 m

Distribution

V21-1027-distribution-map.gif

Ariz., Calif., Idaho, Nev., Oreg., Utah.

Discussion

Though the derived floral features of Chaenactis macrantha obscure its relationships, it may represent a link between sect. Chaenactis (annuals; pappus scales in regular, often strongly reduced series) and sect. Macrocarphus (leaf blades gland-dotted). Resemblance of its heads, leaves, and indument to those of C. thompsonii and relatives is striking. It appears to form no natural hybrids, perhaps because of its nocturnal corollas.

Selected References

None.

Lower Taxa

None.

"longest" is not a number.

... more about "Chaenactis macrantha"
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 +
D. C. Eaton in S. Watson +
decurrent +
compound +  and simple +
lobed;ovate;oblanceolate;ovate;oblanceolate;linear;deltate +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
connate +  and distinct +
Showy or bighead dustymaidens +  and Mojave pincushion +
actinomorphic +
1.2 cm12 mm <br />0.012 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
white +  and pinkish or cream +
stipitate-glandular +  and hairy +
0.9 cm9 mm <br />0.009 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
fertile +  and bisexual +
fertile +  and bisexual +
Ariz. +, Calif. +, Idaho +, Nev. +, Oreg. +  and Utah. +
600–2200 m +
strigose +  and densely sericeous +
scabrellous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
campanulate +  and cylindric +
Open, loose, light-colored, silty, usually calcareous or alkaline, desert soils, often covered by or mixed with gravel +
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 />) +
less obconic;broadly cylindric +
lobed +, plane +, less elliptic +  and ovate +
cauline +  and basal +
1.5 cm15 mm <br />0.015 m <br /> (?) +  and 7 cm70 mm <br />0.07 m <br /> (?) +
deltate +  and more or less lanceolate +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
dentate to pinnatifid or palmatifid +  and entire +
not stipitate-glandular +, arachnoid-sericeous +  and thinly lanuginose +
acute +  and blunt +
2-carpellate +
persistent +
coroniform +
not stipitate-glandular +, arachnoid-sericeous +  and thinly lanuginose distally +
1.5 cm15 mm <br />0.015 m <br /> (8 cm80 mm <br />0.08 m <br />) +
Flowering Mar–early Jul. +
5 +  and 21 +
1.2 cm12 mm <br />0.012 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
arachnoid-sericeous +  and closely lanuginose +
in S. Watson, Botany (Fortieth Parallel), +
bearing subulate enations +, hairy +  and bristly +
knobby;convex;more or less flat +
distinct +
exalbuminous +
unequal +
5 (?) +  and 12 (?) +
usually erect +  and ascending +
1 +  and 5 +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Undefined (tribe Undefined) subtribe Bahiinae +  and Undefined (tribe Undefined) subtribe Palafoxiinae +
Chaenactis macrantha +
Chaenactis sect. Chaenactis +
species +
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 />) +
5 cm50 mm <br />0.05 m <br /> (70 cm700 mm <br />0.7 m <br />) +