Bidens discoidea

(Torrey & A. Gray) Britton

Bull. Torrey Bot. Club 20: 281. 1893.

Common names: Bident discoïde
Endemic
Basionym: Coreopsis discoidea Torrey & A. Gray Fl. N. Amer. 2: 339. 1842
Treatment appears in FNA Volume 21. Treatment on page 211. Mentioned on page 207.

Annuals, (10–) 20–60 (–180) cm. Leaves: petioles 10–40 (–60) mm; blades deltate to lanceovate overall, 30–80 (–100+) × 10–30 (–80+) mm, usually 3-foliolate, leaflets petiolulate, lanceovate to lanceolate, (10–) 20–50 (–100) × 5–20 (–40) mm, bases cuneate, ultimate margins usually serrate, sometimes ciliate, apices acuminate to attenuate, faces glabrous or hirtellous. Heads usually borne singly, sometimes in 2s or 3s. Peduncles 10–20 (–50+) mm. Calyculi of (3–) 4 (–5+) ± appressed, spatulate to linear, seldom foliaceous bractlets or bracts (3–) 12–25 mm, margins seldom ciliate, abaxial faces usually glabrous. Involucres ± hemispheric, 4–5 (–7) × 4–6 (–9) mm. Phyllaries 5–7, oblong to lanceolate, 4–6+ mm. Ray-florets 0. Disc-florets (10–) 15–20+; corollas ± orange, 1.5–2 mm. Cypselae blackish to redbrown or stramineous, ± flattened, linear to narrowly cuneate, outer 3–5 mm, inner 4–6+ mm, margins not distinctly ciliate, apices ± truncate to concave, faces ± tuberculate, antrorsely strigillose; pappi of 2 ± erect, antrorsely barbed or smooth awns (0.2–) 1–2.4 mm. 2n = 24.


Phenology: Flowering Aug–Oct(–Nov).
Habitat: Ponds, swamps, other relatively wet sites
Elevation: 10–300 m

Distribution

V21-514-distribution-map.gif

N.B., N.S., Ont., Que., Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis.

Discussion

Bidens discoidea is not nearly as variable morphologically as the closely related B. vulgata or B. frondosa. It differs from B. frondosa in having smaller heads, cypselae with shorter, antrorsely barbed awns, fewer phyllaries and flowers per head, sparse indument, and leaves with fewer, more acuminate leaflets. Both B. discoidea and B. frondosa differ from B. vulgata in texture of flowers, in heads, and in shapes and surfaces of cypselae (M. L. Roberts 1982, 1983; M. G. Hickler 1999).

Selected References

None.

Lower Taxa

None.
... more about "Bidens discoidea"
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 +
(Torrey & A. Gray) Britton +
ciliate +  and barbellate +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
2 +  and 4 +
0.1 cm1 mm <br />0.001 m <br /> (0.24 cm2.4 mm <br />0.0024 m <br />) +
cuneate +
Coreopsis discoidea +
8 cm80 mm <br />0.08 m <br /> (10 cm100 mm <br />0.1 m <br />) +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
deltate;lanceovate +
10mm;30mm +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
0.3 cm3 mm <br />0.003 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
erect +  and spreading or reflexed +
1.2 cm12 mm <br />0.012 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
barbellulate +  and barbellate +
Bident discoïde +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
blackish +  and redbrown or stramineous +
linear +  and narrowly cuneate +
fertile +  and bisexual +
fertile +  and bisexual +
sessile +  and petiolate +
N.B. +, N.S. +, Ont. +, Que. +, Ala. +, Ark. +, Conn. +, Del. +, D.C. +, Fla. +, Ga. +, Ill. +, Ind. +, Iowa +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, N.H. +, N.J. +, N.Y. +, N.C. +, Ohio +, Okla. +, Pa. +, R.I. +, S.C. +, Tenn. +, Tex. +, Vt. +, Va. +, W.Va. +  and Wis. +
10–300 m +
strigillose +, hirtellous +  and glabrous +
tuberculate +
linear-fusiform;4-angled;ovate;orbiculate;oblong;linear;cuneate +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Ponds, swamps, other relatively wet sites +
discoid +  and radiate +
disciform +  and discoid +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
hemispheric +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
sessile +  and petiolate +
whorled +  and opposite +
5 cm50 mm <br />0.05 m <br /> (10 cm100 mm <br />0.1 m <br />) +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
lanceovate +  and lanceolate +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
deltate +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
2-carpellate +
less flat;slightly navicular +
smooth +  and barbed +
persistent +
of 1-2 , smooth to ciliate or barbed awns or scales +  and coroniform +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
4 cm40 mm <br />0.04 m <br /> (6 cm60 mm <br />0.06 m <br />) +
1 cm10 mm <br />0.01 m <br /> (4 cm40 mm <br />0.04 m <br />) +
Flowering Aug–Oct(–Nov). +
connate +  and distinct +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Bull. Torrey Bot. Club +
styliferous +  and neuter +
bearing subulate enations +, hairy +  and bristly +
convex;flat +
exalbuminous +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Megalodonta +
Bidens discoidea +
species +
toothed +, serrate +, laciniate +  and dentate +
60 cm600 mm <br />0.6 m <br /> (180 cm1,800 mm <br />1.8 m <br />) +
20 cm200 mm <br />0.2 m <br /> (60 cm600 mm <br />0.6 m <br />) +
shrub +  and subshrub +