Bidens tenuisecta

A. Gray

Mem. Amer. Acad. Arts, n. s. 4: 86. 1849.

Treatment appears in FNA Volume 21. Treatment on page 210. Mentioned on page 207.

Annuals, (10–) 20–40 cm. Leaves: petioles 5–40 mm; blades rounded-deltate to ovate overall, 20–50+ × 15–35+ mm, (1–) 2–3-pinnatisect, ultimate lobes ± linear, (2–) 5–15+ × (0.5–) 2–3+ mm, bases ± cuneate, ultimate margins entire, sometimes ciliolate, apices acute to attenuate, faces usually glabrous, sometimes hispidulous. Heads usually borne singly, sometimes in 2s or 3s. Peduncles 20–30 (–80) mm. Calyculi of 6–12 ± appressed, linear bractlets 5–7 mm, margins scabro-ciliate, abaxial faces usually pilosulous to hirsutulous, rarely glabrous. Involucres campanulate to hemispheric or broader, (5–) 6–7 × 4–8 mm. Phyllaries 8, lance-linear, 5–7 mm. Ray-florets 0 or 3–6; laminae yellow, 4–6 mm. Disc-florets (5–) 12–20 (–45); corollas yellow, 2–3 mm. Cypselae: outer redbrown, flat or weakly 4-angled, linear, 6–8 mm, margins not ciliate, apices somewhat attenuate, faces obscurely 2-grooved, often tuberculate, glabrous or ± strigillose; inner similar, blackish (sometimes with pale tips), ± equally 4-angled, linear-fusiform, 8–15 mm, margins not ciliate, apices attenuate, faces 2-grooved, glabrous or, toward tips, strigillose; pappi of 2 (–3), spreading to divergent, retrorsely barbed awns (1–) 1.5–3 mm.


Phenology: Flowering (Jul–)Aug–Sep(–Oct).
Habitat: Meadows, along streams
Elevation: 1800–2600 m

Distribution

V21-510-distribution-map.gif

Ariz., Colo., Idaho, N.Mex., Utah, Mexico (Chihuahua)

Discussion

Reports of Bidens tenuisecta from Maryland, Massachusetts, and New York may be based on ephemeral introductions.

Selected References

None.

Lower Taxa

None.
... more about "Bidens tenuisecta"
glabrous +, usually pilosulous +  and hirsutulous +
not tailed +, rounded +  and obtuse +
dark +  and pale +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
indeterminate +  and determinate +
John L. Strother +  and Ronald R. Weedon +
A. Gray +
ciliate +  and barbellate +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
cuneate +
compound +  and simple +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
rounded-deltate;ovate +
15mm;35mm +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
erect +  and spreading or reflexed +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
barbellulate +  and barbellate +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
subterete +, linear-fusiform +, 4-angled +, cuneate +  and oblanceolate or obovate +
fertile +  and bisexual +
fertile +  and bisexual +
sessile +  and petiolate +
Ariz. +, Colo. +, Idaho +, N.Mex. +, Utah +  and Mexico (Chihuahua) +
1800–2600 m +
strigillose +, , +, glabrous +  and hispidulous +
tuberculate +
linear-fusiform;4-angled;ovate;orbiculate;oblong;linear;cuneate +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Meadows, along streams +
discoid +  and radiate +
disciform +  and discoid +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
linear-fusiform +  and 4-angled +
0.8 cm8 mm <br />0.008 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.4 cm4 mm <br />0.004 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 />) +
campanulate;hemispheric +
0.4 cm4 mm <br />0.004 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
sessile +  and petiolate +
whorled +  and opposite +
deltate +
not ciliate +  and scabro-ciliate +
4-angled +  and flat +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
2-carpellate +
less flat;slightly navicular +
persistent +
of 1-2 , smooth to ciliate or barbed awns or scales +  and coroniform +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (4 cm40 mm <br />0.04 m <br />) +
Flowering (Jul–)Aug–Sep(–Oct). +
connate +  and distinct +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Mem. Amer. Acad. Arts, n. s. +
styliferous +  and neuter +
bearing subulate enations +, hairy +  and bristly +
convex;flat +
exalbuminous +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Megalodonta +
Bidens tenuisecta +
species +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
toothed +, serrate +, laciniate +  and dentate +
10 cm100 mm <br />0.1 m <br /> (20 cm200 mm <br />0.2 m <br />) +
20 cm200 mm <br />0.2 m <br /> (40 cm400 mm <br />0.4 m <br />) +
shrub +  and subshrub +