Flora of North America species comparison

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Clematis occidentalis

Clematis vitalba

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

evergreen clematis, old-man's beard, Traveler's-joy, Traveler's-joy clematis, white virgin's-bower
Stems

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

climbing with tendril-like petioles and leaf-rachises, to 12 m. Leaf blade pinnately 5-foliolate;

leaflets cordiform, 8 × (2-)3-5(-6) cm, margins entire to regularly crenate or dentate;

surfaces abaxially minutely pubescent on veins, adaxially glabrous.
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 and terminal, (3-)5-22-flowered cymes.
Flowers

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

bisexual;

pedicel 1-1.5 cm, slender;

sepals wide-spreading, not recurved, white to cream, elliptic or oblanceolate to obovate, ca. 1 cm, length ca. 2 times width, abaxially and adaxially tomentose;

stamens ca. 50;

filaments glabrous;

staminodes absent;

pistils 20 or more.
Achenes

nearly terete, not conspicuously rimmed, densely pubescent;

beak ca. 3.5 cm.

Clematis occidentalis

Clematis vitalba
Phenology Flowering summer (Jun–Aug).
Habitat Roadsides, waste ground, secondary growth
Elevation 0-100 m (0-300 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
ME; OR; WA; BC; ON; native to Europe; n Africa [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 vitalba is naturalized in only a few sites in eastern North America and northwestern Oregon to the Puget Sound.

(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. orientalis, C. pauciflora, C. pitcheri, C. recta, C. reticulata, C. socialis, C. tangutica, C. terniflora, C. texensis, C. versicolor, C. viorna, C. virginiana, C. viticaulis, C. viticella
Subordinate taxa
C. occidentalis var. dissecta, C. occidentalis var. grosseserrata, C. occidentalis var. occidentalis
Synonyms Atragene occidentalis
Name authority (Hornemann) de Candolle: Prodr. 1: 10. (1824) Linnaeus: Sp. Pl. 1: 544. (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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