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Van brunt’s jacob’s-ladder (Polemonium vanbruntiae) COSEWIC assessment and status report: chapter 3

Species Information

Name and classification

Scientific name:

Polemonium vanbruntiae Britton

Relevant synonyms:

Polemonium van-bruntiae Britton, Polemonium caeruleum L. subsp. vanbruntiae (Britt.) Davidson

Name of the order:

Solanales

Name of the family:

Polemoniaceae

French common names:

polémoine de Van Brunt, polémonium de Van Brunt

English common names:

Van Brunt’s Jacob’s-ladder, Appalachian Jacob’s-ladder, Eastern Jacob’s-ladder

Comment on the taxonomy:

Until just recently, the specific epithet van-bruntiae was used in the scientific name. The epithet vanbruntiae, which complies with the International Code of Botanical Nomenclature, was officially used by the Ministère de l’Environnement du Québec for the first time in 1998 (Couillard, 1998; Gouvernement du Québec, 1998), but it had already been used by American authors (Johnson and Murray, 1988; Thompson, 1991).

Description

Herbaceous perennial emerging from a horizontal rhizome. Stems upright, 40-140 cm tall, glabrous, robust and single. Leaves alternate, compound, 2-50 cm long and 1.5-10 cm wide, glabrous; leaflets shortly petiolate, opposite or almost opposite, 1-3.5 cm apart, acuminate, entire; lower leaves with 15 to 21 ovate leaflets 15-60 mm long and 5-25 mm wide, upper leaves with 7 to 15 lance-oblong leaflets; inflorescence bracts glabrous or glandular-pubescent (Figure 1).

Inflorescence a rather narrow panicle, slightly glandular-pubescent. Flowers few, 2 to 8 per branch, scentless; pedicels densely glandular-pubescent, 2-15 mm long; calyx purple-green (at anthesis) to yellowish-green (at maturity), persistent; sepals 5, 8-17 mm long and 4-6 mm wide, pubescent with hairs up to 2 mm long, slightly glandular; corolla blue-violet and yellowish-green at the base, 15-25 mm in diameter, glabrous, tubular at the base; corolla lobes 5, 12-20 mm long and 7-10 mm wide; stamens 5, strongly exserted, 12-18 mm long, protruding 4-7 mm from corolla; anthers orange-yellow, 2-5 mm long; filaments white, villose at the base; style exserted, blue-violet, slightly longer than the stamens; stigma generally trilobate.  Fruit an ovoid capsule, 5-7 mm long, 3-4 mm wide, generally 3-locular, sometimes 4- to 7-locular; seeds brownish-black, 1-10 per locule, slightly winged. 2n = 18, 36.

Figure 1.  Polemonium vanbruntiae (drawing by Réjean Roy).

Figure 1.  Polemonium vanbruntiae (drawing by Réjean Roy).

 

Polemonium vanbruntiae may be confused with P. caeruleum and P. reptans, two species introduced and cultivated in Canada, which occasionally escape near gardens and in disturbed habitats. The main differences between the three species are outlined below:
  P. caeruleum P. reptans P. vanbruntiae
1. Stamens and style slightly exserted or level with the corolla. inserted or level with the corolla. strongly exserted.
2. Stems 20-90 cm tall, upright. 15-50 cm tall, spreading or prostrate. 40-140 cm tall, upright.
3. Lower leaf leaflets 19-29, lance-oblong, up to 10 mm wide. 11-17, lanceolate to ovate, up to 20 mm wide. 15-21, ovate, up to 25 mm wide.
4. Sepals 5-9 mm long. 5-8 mm long. 8-17 mm long.
5. Habitat roadsides, waste ground. rich woods. moist open and semi-open habitats.

Readily available works providing the best descriptions include: Davidson (1950); Fernald (1950); Gleason and Cronquist (1991); Thompson (1991); Sabourin and Paquette (1992, 1994); Couillard (1998); Coursol (2001); Ministère de l’Environnement du Québec (2001); NatureServe (2001). Figure 1 illustration of Polemonium vanbruntiae was drawn by Réjean Roy.

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