Flora of North America species comparison

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Clematis occidentalis

Clematis occidentalis var. occidentalis

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
Photo is of parent taxon

western blue virginsbower
Stems

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

± viny, climbing or trailing, 0.25-3.5 m. Leaves: leaflets unlobed or occasionally 1-3-lobed, (2-)3-6(-10) cm, margins entire or shallowly crenate-serrate.
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.

Flowers

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

sepals remaining moderately divergent, reddish violet, ovate to oblong-elliptic, 2.5-6 cm, margins not fluted, tips rounded-mucronate to nearly acuminate.
2n

= 16.

Clematis occidentalis

Clematis occidentalis var. occidentalis
Phenology Flowering spring.
Habitat Calcareous cliffs, rock ledges, talus slopes, gravelly embankments, rocky woods, and clearings
Elevation 0-1300 m (0-4300 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
CT; DE; IA; IL; MA; MD; ME; MI; MN; NC; NH; NJ; NY; PA; RI; VA; VT; WI; WV; NB; ON; QC
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

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

Clematis occidentalis var. occidentalis formerly occurred in Ohio. Plants in the western part of the range of this variety tend to have larger, more abruptly tapering sepals; they have been segregated as var. grandiflora B.Boivin, but they do not appear to constitute a distinct taxon.

(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. Atragene > Clematis occidentalis
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. occidentalis var. dissecta, C. occidentalis var. grosseserrata
Subordinate taxa
C. occidentalis var. dissecta, C. occidentalis var. grosseserrata, C. occidentalis var. occidentalis
Synonyms Atragene occidentalis Atragene americana, C. verticillaris, C. verticillaris var. cacuminis, C. verticillaris var. grandiflora
Name authority (Hornemann) de Candolle: Prodr. 1: 10. (1824) unknown
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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