Horkelia sect. Capitatae

(Rydberg) O. Stevens in N. L. Britton et al.

in N. L. Britton et al., N. Amer. Fl. 22(7): 7. 1959.

Endemic
Basionym: Capitatae Rydberg Monogr. N. Amer. Potentilleae, 122. 1898
Synonyms: Potentilla sect. Capitatae (Rydberg) Crum
Treatment appears in FNA Volume 9. Treatment on page 259. Mentioned on page 248.

Plants forming tufts or open mats, green or reddish, rarely grayish, conspicuously glandular, resinously aromatic. Stems ascending to erect, (0.6–) 1–6 (–9) dm. Basal leaves planar; stipules entire; leaflets 3–8 (–15) per side, separate, sometimes ± overlapping, divided 1/5–3/4+ to midrib into (3–) 5–15 teeth or lobes not restricted to apex. Inflorescences open to ± congested, flowers usually arranged in ± capitate glomerules, arranged individually in H. fusca var. filicoides. Pedicels remaining ± straight, outermost sometimes ± reflexed in congested inflorescences, 1–3 (–10) mm. Flowers: epicalyx bractlets linear, 0.2–0.3 (–0.5) mm wide, entire; hypanthium interior glabrous; sepals acute to acuminate; petals white to pale-pink, often veined with pink to rose, ± oblanceolate to cuneate, apex emarginate to truncate or rounded; filaments white, glabrous, anthers longer than wide; carpels 10–25. Achenes 1–1.8 mm, smooth.

Distribution

w United States

Discussion

Species 1.

Rydberg recognized seven species in his group Capitatae, treated here as intergrading variation within a single species. Plants of the section share the characteristic Horkelia odor, glandularity, and planar leaves of sect. Horkelia, but differ in the combination of relatively small, short-pedicelled flowers that (except for var. filicoides) are most commonly aggregated into one or more capitate, purple-suffused glomerules, with linear epicalyx bractlets, oblanceolate-cuneate petals that are often pink-tinged, and relatively short, broad filaments.

Selected References

None.

Lower Taxa

"dm" is not declared as a valid unit of measurement for this property.

... more about "Horkelia sect. Capitatae"
1mm +  and 1.8mm +
longer than wide +
pink +  and rose +
Barbara Ertter +  and James L. Reveal +
(Rydberg) O. Stevens in N. L. Britton et al. +
compound +  and simple +
opposite +  and alternate +
flattened +
Capitatae +
30 cm300 mm <br />0.3 m <br /> (40 cm400 mm <br />0.4 m <br />) +
planar +  and cylindric +
2 cm20 mm <br />0.02 m <br /> (30 cm300 mm <br />0.3 m <br />) +
reduced +
free +  and distinct +
open to congested +
w United States +
not +  and aggregated +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
flattened +
0.4 cm4 mm <br />0.004 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
obliquely ovoid +  and reniform +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0 +  and 1/2 +
0.1 cm1 mm <br />0.001 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
crassinucellate +
opposite +  and alternate +
marcescent +
winter-persistent +
overlapping +  and separate +
oblanceolate +
palmate +  and pinnate +
shallowly toothed +  and deeply divided +
inferior +  and superior +
clustered +, biseriate +  and superposed +
0.3 cm3 mm <br />0.003 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0 (?) +  and 4 (?) +
free +  and distinct +
adnate +, free +, connate +  and distinct +
in N. L. Britton et al., N. Amer. Fl. +
not arillate +
persistent +
free +  and distinct +
erect +, spreading +  and strongly reflexed +
acute +  and acuminate +
free +  and distinct +
branched +  and simple +
stramineous +, reddish +  and green +
ascending +  and erect +
1 +  and 10 +
palmate +  and pinnate +
deciduous +
distinct +
subterminal +
filiform +
rough-thickened +
Potentilla sect. Capitatae +
Horkelia sect. Capitatae +
Horkelia +
section +
5 +  and 15 +
inconspicuous +
enlarged +
grayish +, reddish +  and green +
hairy +  and inconspicuously conspicuously glandular +