Flora of North America species comparison

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Clematis occidentalis

Clematis orientalis

blue clematis, clématite occidentale, Columbia bower, Columbia clematis, Columbia virgin's bower, purple clematis, purple virgin's-bower, rock clematis, western blue clematis, western blue virginsbower, western clematis

Chinese clematis, oriental clematis, oriental virginsbower
Stems

viny, climbing or trailing (plants scarcely viny perennials in var. dissecta).

climbing, 2-8 m. Leaf blade pinnately 5-7-foliolate, proximal leaflets sometimes 3-foliolate;

leaflets lanceolate to elliptic or ovate, usually 2-3-lobed proximally, 1-5.5 × 0.5-3.5 cm, margins entire or coarsely few-toothed;

surfaces at least abaxially pubescent, glaucous.
Leaf

blade 1-ternate (or terminal leaflet sometimes ternate in var. dissecta), ± firm but not succulent;

leaflets lance-ovate to triangular or suborbiculate, lobed or unlobed, margins entire or toothed.

Inflorescences

axillary, sometimes terminal, 3-many-flowered cymes or flowers solitary.
Flowers

sepals violet-blue, reddish violet, or white, lanceolate to ovate or elliptic-oblong.

bisexual;

pedicel (0.5-)1-11 cm;

sepals wide-spreading and recurved, greenish yellow, ovate-lanceolate to elliptic, 0.8-2 cm, length ca. 2.5 times width, margins densely pubescent, abaxially and adaxially pubescent or abaxially glabrous;

stamens 20-40;

filaments pilose proximally;

staminodes absent;

pistils 75-150.
Achenes

turgid, not conspicuously rimmed, pilose;

beak 2-5 cm.

Clematis occidentalis

Clematis orientalis
Phenology Flowering summer–fall.
Habitat Roadsides, other secondary habitats, open woods
Elevation 0-2600 m (0-8500 ft)
Distribution
from FNA
CO; CT; DE; IA; ID; IL; MA; MD; ME; MI; MN; MT; NC; NH; NJ; NY; OR; PA; RI; UT; VA; VT; WA; WI; WV; WY; AB; BC; NB; ON; QC; SK; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; NM; NV; UT; ON; native to Eurasia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Clematis orientalis has been reported from Idaho; it probably can be expected elsewhere.

This species has been divided by C. Grey-Wilson (1989) into five varieties, partly correlated with their distribution in Asia. Naturalized plants in North America seem best referred to C. orientalis var. robusta Grey-Wilson, native to Afghanistan.

Although Clematis orientalis has been naturalized in the Rocky Mountains since the late nineteenth century, it has spread especially rapidly since ca. 1975, becoming weedy and, in some localities, constituting a threat to young trees and native shrubby and herbaceous species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Leaflets lobed or unlobed, margins entire or crenate-serrate (or terminal leaflet sometimes ternate); stems tufted or, if viny, up to 0.5(–1.5) m.
var. dissecta
1. Leaflets unlobed or some 1–3-lobed, margins entire or shallowly serrate; stems ± viny, climbing or trailing, 0.25–3.5 m.
→ 2
2. Sepals reddish violet, rounded-mucronate to nearly acuminate.
var. occidentalis
2. Sepals violet-blue to pale blue, rarely white, usually distinctly acuminate.
var. grosseserrata
Source FNA vol. 3. FNA vol. 3.
Parent taxa Ranunculaceae > Clematis > subg. Atragene Ranunculaceae > Clematis > subg. Clematis
Sibling taxa
C. addisonii, C. albicoma, C. baldwinii, C. bigelovii, C. catesbyana, C. coactilis, C. columbiana, C. crispa, C. drummondii, C. fremontii, C. glaucophylla, C. hirsutissima, C. lasiantha, C. ligusticifolia, C. morefieldii, C. ochroleuca, C. orientalis, C. pauciflora, C. pitcheri, C. recta, C. reticulata, C. socialis, C. tangutica, C. terniflora, C. texensis, C. versicolor, C. viorna, C. virginiana, C. vitalba, C. viticaulis, C. viticella
C. addisonii, C. albicoma, C. baldwinii, C. bigelovii, C. catesbyana, C. coactilis, C. columbiana, C. crispa, C. drummondii, C. fremontii, C. glaucophylla, C. hirsutissima, C. lasiantha, C. ligusticifolia, C. morefieldii, C. occidentalis, C. ochroleuca, C. pauciflora, C. pitcheri, C. recta, C. reticulata, C. socialis, C. tangutica, C. terniflora, C. texensis, C. versicolor, C. viorna, C. virginiana, C. vitalba, C. viticaulis, C. viticella
Subordinate taxa
C. occidentalis var. dissecta, C. occidentalis var. grosseserrata, C. occidentalis var. occidentalis
Synonyms Atragene occidentalis Viticella orientalis
Name authority (Hornemann) de Candolle: Prodr. 1: 10. (1824) Linnaeus: Sp. Pl. 1: 543. (1753)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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