Clematis subg. Atragene

(Linnaeus) Torrey & A. Gray

Fl. N. Amer. 1: 10. 1838.

Basionym: Undefined subg. Atragene Linnaeus Sp. Pl. 1: 542. 1753, Gen. Pl. ed.5, 241. 1754
Treatment appears in FNA Volume 3. Mentioned on page 165.

Woody vines or rhizomatous herbs with short, tufted stems. Leaf-blade 1-3-ternate, lobed or unlobed, margins entire or coarsely serrate. Inflorescences terminal on short-shoots or rarely terminal on long-shoots, 1 [-2] -flowered with bractless peduncles subtended by 1 or 2 pairs of leaves. Flowers bisexual, ± nodding; perianth widely bell-shaped to rotate; sepals ascending or tardily spreading, not connivent, usually violet-blue, sometimes reddish violet, or white, ovate to oblong, thin, margins densely pubescent, abaxially sparsely pubescent; staminodes present between stamens and sepals, flattened, petaloid, bearing reduced, sterile anthers; filaments flattened, pubescent at least on margins. Achenes flattened; beak over 2 cm, plumose.

Distribution

Temperate to subarctic and subalpine North America and Eurasia

Discussion

Species ca. 5 (2 in the flora).

F. B. Essig (1992) suggested that Clematis subg. Atragene might be included in Clematis subg. Clematis. Because of its distinctive inflorescence and floral morphology, however, and because it has not been successfully crossed with species in any other subgenus, its subgeneric status is retained here.

The two North American species have been known to hybridize in Montana.

Selected References

None.

Key

1 Leaf blade consistently 2–3-ternate. Clematis columbiana
1 Leaf blade 1-ternate (or terminal leaflet sometimes ternate in var. dissecta). Clematis occidentalis

"thin" is not a number.

... more about "Clematis subg. Atragene"
flattened +
flattened +
reduced +
James S. Pringle +
(Linnaeus) Torrey & A. Gray +
cuneate +, truncate +  and cordate +
Undefined subg. Atragene +
curved +  and straight +
plumose +
1.2 cm12 mm <br />0.012 m <br /> (11 cm110 mm <br />0.11 m <br />) +
scale-like;leaflike +
globose;cylindric +
1-many-flowered +
0 cm0 mm <br />0 m <br /> (15 cm150 mm <br />0.15 m <br />) +
Temperate to subarctic and subalpine North America and Eurasia +
flattened +
1-many-flowered +
showy +  and inconspicuous +
0 cm0 mm <br />0 m <br /> (15 cm150 mm <br />0.15 m <br />) +
sessile +  and aggregate +
flattened-ellipsoid;terete;flattened-ellipsoid;terete;lenticular +
terminal +  and axillary +
unlobed +  and lobed +
petiolate +, sessile +, compound +  and simple +
cordate +  and orbiculate oblong lanceolate or oblanceolate lobed or unlobed +
cordate +  and orbiculate oblong lanceolate or oblanceolate lobed or unlobed +
palmate +  and pinnate +
serrate +  and entire +
toothed;entire +
1-many-flowered +
0 cm0 mm <br />0 m <br /> (15 cm150 mm <br />0.15 m <br />) +
widely bell-shaped;rotate +
distinct +
conspicuous +
spurred +, funnel--shaped +, cup-shaped +  and plane +
reduced +
5 +  and 150 +
Fl. N. Amer. +
not arillate +  and stalked +
not connivent +
white;reddish violet;white;reddish violet;violet-blue +
not persistent +
distinct +
spreading +  and ascending +
3 +  and 6 +
ovate +  and oblong +
0.6 cm6 mm <br />0.006 m <br /> (6 cm60 mm <br />0.06 m <br />) +
persistent +
Clematis subg. Atragene +
Clematis +
subgenus +
annual +  and perennial +